CHAP. VI.

 

Experiments on Generation.

 

            I Often [sic] reflected on the above two systems of generation, and was daily more and more convinced that my theory was infinitely more probable.  At length I began to suspect that these living organic particles, fro which I thought all animals and vegetables derived their origin, might be recognized, by the assistance of good glasses.  My first notion was, that the spermatic animalcules found in the seminal fluid of all males, might probably be these very organic particles; and I reasoned in this manner.  If all animals and vegetables contain an infinite number of organic particles, these particles should be most abundant in their seeds, because the seed is an extract from all the organic parts, and especially from those which are most analogous to the individual:  Perhaps the spermatic animals found in the semen of males may actually be those very organic particles, or at least, the first union or assemblages of then.  But, if this be the case, then the semen of females ought to contain organic living particles, or animalcules, similar to [148] those of the male.  They ought, for the same reason, to be found in the seeds of plants, in the nectarium, and in the stamina, which are the most essential parts of vegetables, and contain the organic particles necessary for their reproduction.  I therefore determined to examine with the microscope the seminal liquors of males and females, and the germs of plants; and, at the same time, I imagined that the cavities of the glandular bodies of the uterus might be the reservoirs of the female semen.  Having communicated my ideas of this subject to my ingenious friends Mr Needham, M. Daubenton, M. Gueneau, and M. Dalibard, they encouraged me to commence a set of experiments in order to throw light upon this mysterious operation of nature.  All of these gentlemen occasionally attended and assisted me; but particularly M. Daubenton, who was never absent, and who was witness to every experiment I made.

 

             I employed a double microscope, which I had from Mr Needham, being the same with which he made his numerous and ingenious observations.*  This instrument is infinitely preferable to those employed by Leeuwenhoek.+ [149]

 

EXPERIMENT 1.

 

            Having procured the seminal vessels of a man who died a violent death, and whose body was still warm, I extracted all the liquor from them, and put it in a vial.  I examined, by the microscope, a drop of this liquor, without any dilution.  As soon as the vapours, which arose from the liquor, and obscured the glass, were dissipated, I observed pretty large filaments [plate I. fig. 1], which, in some places, spread out into branches, and, in others, intermingled with each other.  These filaments clearly appeared to be agitated with an internal undulatory motion, like hollow tubes, which contained some moving substance.  I saw distinctly [pl. I. fig. 2.] two of these filaments, which were joined longitudinally, separate from each other in the middle, and alternately approach and recede, like two stretched cords, fixed by the ends, and drawn asunder at the middle.  These filaments were composed of globules which touched one another, and resembled a chaplet of beads.  I then observed filaments [pl. I. fig. 3.] which were blown up, and swelled in certain places, and perceived small oval globules issue from these swelled parts, which had a vibratory motion, like that of a pendulum [pl. I. fig. 4]  These small bodies were attached to the filament by little threads, [150] which gradually lengthened as the bodies moved:  And, lastly, I observed these small bodies detach themselves entirely from the large filament, and draw after them the little thread, which resembled a tail.  As the liquor was too thick, and the filaments too near each other, I diluted another drop with pure rain water, after satisfying myself that it contained no animalcules.  I then perceived that the filaments were more distant from each other, and saw distinctly the motion of the small bodies above taken notice of, [pl. I. fig. 5.] which were more free, and they appeared to swim with greater agility, and trailed their threads after them with greater ease; and, if I had not seen them separate from the filaments, and draw the threads out of them, I should have believed, from the second observation, the moving bodies to be real animals, and their threads to be tails.  After examining with great attention one of the filaments, which was three times thicker than the small bodies, I perceived two of those bodies detach themselves with much difficulty, and drag after them long slender threads, which impeded their motion.

 

            This seminal liquor was at first too thick.  But it gradually became more fluid, and, in less than an hour, it was almost transparent; and, in proportion as its fluidity augmented, the phaenomena changed, in the manner to be just mentioned.  [151]

 

EXPER. II

 

            When the seminal liquor became more fluid, the filaments disappeared; but the small bodies were exceedingly numerous [pl. I. fig. 6].  Their motion, for the most part, resembled that of a pendulum; each of them had a long thread, from which they evidently endeavoured to disengage themselves; their progressive motion was extremely slow, during which they vibrated to the right and left.  At each vibration, they had a rolling unsteady motion; so that, besides their horizontal vibrations, they roll or vibrate in a vertical direction; which proves these bodies to be of a globular figure, or at least that their inferior part is not a flat base sufficiently extensive to keep them in one position.

 

EXPER. III.

 

            At the end of two or three hours, when the liquor was more fluid, a still greater number of these moving bodies appeared [pl. II. fig. 7.]  They were more free of incumbrances; their threads were shorter; their progressive motion was more direct; and their horizontal vibration was greatly diminished; for the longer the threads are, their vibratory motion was increased, [152] and their progress forward was diminished.  The vertical vibration was still apparent.

 

EXPER. IV.

 

            In five or six hours, the liquor had almost all the fluidity it could acquire, without being decomposed.  We then discovered [pl. II. fig. 8.] that most of these small moving bodies were entirely disengaged from their threads.  Their figure was oval:  They moved forward with considerable quickness; and, by their motion backward and forward, and to every side, they had now more than ever the appearance of real animals.  Those which had tails or threads sticking to them, seemed to have less vivacity than the others.  Of those which had no threads, some appeared to change both their figure and their size.  Some of them were round; but the greatest part of them were oval, and a few of them were thicker at the extremities than in the middle.  The rolling and vibratory motions were still perceptible.

 

EXPER. V.

 

            In 12 hours, the liquor had deposited, at the bottom of the vial, a kind of gelatinous, bluish, or rather ash-coloured substance; and the fluid [153] that swimmed on the top was nearly as clear as water, only it had a tincture of blue, like water in which a small quantity of soap had been dissolved.  It still, however, retained its viscosity.  The little bodies, which were now entirely freed from their threads, moved with great activity on all sides, and some of them turned round their centres.  Most of them were oval, though some of them were round.  I have seen them change figures, and from oval become round:  I have seen them divide, and, from a single oval or globule, separate into two.  Their activity always increased as their size diminished.

 

EXPER. VI.

 

            At the end of 24 hours, the liquor had deposited a greater quantity of gelatinous matter, which I diluted, with some difficulty, in water.  It appeared to consist of a multitude of opaque tubes, resembling lace, but without any regularity or the smallest motion.  In the clear semen itself, there were a few small bodies still moving; next day their number was still farther diminished.  After this, nothing was to be seen but globules without the least appearance of motion.

 

            These experiments were often repeated with great exactness; and they convinced me that the threads which adhere to the moving bodies are not tails, nor any part proper to these bodies; [154] [PLATE III HERE] for the tails or threads have no proportion to the rest of the body; they are of different dimensions, though the bodies are always nearly of the same size at the same time.  The motion of the globule is embarrassed in proportion to the length of the tail.  When the tail is too long, it sometimes prevents the progressive motion altogether, leaving nothing but the vibrations from right to left; and the globules make evident efforts to disentangle themselves from this incumbrance.

 

EXPER. VII.

 

            Having procured the seminal fluid of another man recently dead, I put a pretty large drop of it on the glass, which soon liquified [sic] without any mixture.  It had the appearance of a close network, the filaments of which were of a considerable length and thickness, and they seemed to proceed from the thickest part of the liquor, [pl. II. fig. 9].  These filaments separated in proportion as the liquor became more fluid; and at last they divided into globules, which seemed at first to have too little force to put them in motion:  But their power of moving increased as they receded from the filaments, and they appeared to make considerable efforts to disengage themselves.  In this manner each of them gradually drew tails of different lengths out of the [155] filaments.  Some of these tails were so long and so thin, that they had no proportion to the bodies, which were always more or less embarrassed, according to the length of the threads or tails.  When the tail was long, the angle of the vibratory motion was increased; and, when the tail was short, the progressive motion was more conspicuous. 

 

EXPER. VIII.

 

            I continued my observations, almost without interruption, for 14 hours, and I discovered, that the length of the tails or threads gradually diminished, and became so thin and delicate, that their extremities successively ceased to be visible; and at last the whole disappeared.  The horizontal vibrations of the globules then ceased, and their progressive motion was direct, though they still had vertical oscillations, or rather, they rolled like a vessel at sea.  The small bodies, when deprived of their tails, were oval and transparent, and resembled those pretended animals which are seen in oyster-water on the 6th or 7th day, or those found in the jelly of roasted veal at the end of the 4th day.

 

EXPER. IX.

 

            Between the 10th and 12th hour, the liquor was become very fluid, and all the globules ap- [156] peared to proceed in troops from one side of the drop [pl. II. fig. 10.].  They passed over the field of the microscope in less than four seconds; they marched in lines of seven or eight in front; and succeeded each other without interruption, like the defiling of soldiers.   I observed this singular phaenomenon for more than five minutes; and, as the current of animals did not then cease, I was desirous of discovering the cause.  I therefore gently shifted the glass, and perceived that all these moving globules proceeded from a kind of mucilage, [pl. II. fig. 11.].  or net-work of filaments, which continually produced them, and with more rapidity and copiousness than the filaments had done ten hours before.  There was still a difference more remarkable between the globules produced by the liquor when thick, and those produced when it was more fluid; for, in the latter case, they drew no threads or tails after them, their motion was quicker, and they went in flocks like sheep.  I examined the mucilage from which they proceeded for a long time, and perceived that it gradually diminished and was converted into moving globules, till more than one half of it was destroyed.  After which, the liquor being too dry, this mucilage became obscure in the middle, and it was surrounded with small threads, forming square intervals, [pl. II. fig. 12.].  These small threads seemed to be composed of the bodies of the moving globules which had been killed by the drying of [157] the liquor, and the whole resembled the web of a spider besprinkled with drops of dew.

 

EXPER. X.

 

            By the first experiments, I perceived that these small moving bodies changed their figures; and I imagined, that, in general, they diminished in bulk, though I was not then altogether certain of the fact.  But my subsequent observations removed every doubt.  At the 12th and 13th hour, the bodies were visibly smaller; but, as they diminished in bulk, their specific gravity increased, especially when they ceased to move, which they generally did all at once, and fell down to the bottom in the form of an ash-coloured sediment, which was perceptible by the naked eye; and, by the assistance of the microscope, it appeared to be composed of globules attached to one another, sometimes by threads, and at other times in groups, but always in a regular manner.

 

EXPER. XI.

 

            Having procured the fresh semen of a dog, I observed that this liquor was clear, and had very little tenacity.  I examined it without the addition of water, and I perceived moving bodies [158] [PLATE 4 HERE] almost entirely similar to those in the human semen, [Pl. III. fig. 13.].  Their tails and their form were almost precisely the same with those represented in Pl. II. fig. 7. where the liquor had been liquified [sic] for two or three hours.  I in vain searched this liquor for the filaments which appeared in that of men.  I only remarked some long and very delicate threads, exactly similar to those which served for tails to the globules.  These threads contained no globules; neither had they any motion.  The globules with tails seemed to move with more vivacity than those in the human semen.  They had hardly any horizontal vibrations; but they always rolled vertically.  Their number was not great; and, though their progressive motion was quicker, they took up some time in passing over the field of the microscope.  I examined this liquor during three hours, and could observe no change.  I continued my examination, from time to time, for several days, and remarked, that the number of moving bodies gradually diminished.  On the second day, the greatest part of them had lost their tails:  On the third, very few of them retained their tails; on the fourth, however, some tails still adhered.  The liquor had now deposited a whitish sediment, which appeared to be composed of globules without motion, and some small threads that seemed to be the tails which had separated from the globules.  Some globules appeared to have dead one attached to [159] them; for their figure differed from that of those in motion, [Pl. III. fig. 14.]:  They were larger than the moving globules, or the dead ones at the bottom of the liquor, and seemed to have a kind of fissure or opening.

 

EXPER. XII.

 

            At another time I examined the seminal fluid of the same dog, and perceived the same phaenomena which have been described.  I farther observed, in a drop of this liquor, a mucilaginous part, [Pl. III. fig. 15.] from which globules issued as in Exper. IX. And these globules formed a current, and moved in regular troops.  This mucilage appeared to be agitated internally with a swelling or undulating motion, which produced small protuberances in different parts; and these protuberances issued suddenly in the form of globules, which moved briskly forward in the same direction.  These globules differed not from the others, excepting that they issued from the mucilage without tails.  Some of them, I remarked, changed their figure; they resembled small cylinders; after which the extremities of the cylinders swelled, and divided by the middle into two globules, and both of them moved on in the same direction with the rest.

 

EXPER. XIII.

 

            The small glass which contained this liquor having been overturned by accident, I took, from the same dog, another quantity of semen.  But, whether this animal had been fatigued by two frequent emissions, or from some other cause, this seminal liquor contained nothing:  It was transparent and viscous, like the serum of blood; and, though I examined it, at different times, for 24 hours, I could perceive no moving bodies, no mucilage, nor, in a word, any thing similar to what I had formerly seen.

 

EXPER. XIV.

 

            I then opened a dog, and took out the testicles, and the vessels adhering to them.  But I remarked, that he had no seminal vessels:  The seed of this animal probably passes directly from the testicles into the urethra.  Though the dog was full grown and vigorous, I found very little semen in the testicles.  I examined with the microscope the small quantity I could collect; but could perceive no moving bodies:  I only saw a great number of very minute globules, the greatest part of which were motionless; and some of the smallest of them seemed to move towards each other.  But of this I could not be [161] certain; because the small drops dried in a minute or two after they were put upon the glass.

 

EXPER. XV.

 

            I cut the testicles of this dog into two parts, put them into a glass-vessel, with as much water as was sufficient to cover them, and corked up the glass.  Three days after, I examined this infusion with a view to discover if the flesh contained any moving bodies, and I perceived in the water of this infusion a great number of moving bodies, some of them of a globular, others of an oval figure, and entirely resembling those I had seen in the seminal fluid of the dog, excepting that they had no threads or tails:  they moved in all directions with great vivacity.  I observed, during a long time, these bodies, which appeared to be animated, and I perceived several of them change their figures before my eyes.  Some of them lengthened, others contracted, and others swelled at the two extremities.  The whole of them seemed to turn on their centres; some of them were larger, and other smaller; but the whole were in motion, and resembled, both in size and figure, those which were described in Exper. IV.  [162]

                                                                                             

EXPER. XVI.

 

            Next day, the number of moving globules was still increased; but they were smaller; their motion more rapid and more irregular; and their form and manner of moving were different, and appeared to be more confused:  The day after, and the following days, till the 20th, moving bodies still appeared in this water.  They daily diminished in size, and at last became so small that they could be hardly perceived; but the last of them I was able to distinguish on the 18th and 20th days, moved with the same rapidity as ever.  On the top of the water there was a pellicle which appeared to be composed of the skins or coverings of the moving bodies, of small threads, &c.  But no motion appeared in it.  This pellicle and the moving bodies could not be introduced into the liquor by means of the external air; for the bottle was always closely corked.

 

EXPER. XVII.

 

            I opened successively, on different days, ten rabbits, in order to examine their seminal fluid.  In the first, second, and third, I found not a single drop, either in the testicles or seminal vessels, though I was certain that two of them were [163] fathers of a numerous progeny.  I imagined that the presence of the female might be necessary for the secretion of the semen; I therefore put males and females by pairs into separate cages, so constructed that they could not possibly copulate.  Neither did this scheme at first succeed; for I opened two of them without finding any semen.  In the sixth, however, which was a large white rabbit, full of vigour, I found as much liquor in the seminal vessels as would fill a small coffee-spoon.  This matter resembled the jelly of meat, was of a citron colour, and almost transparent.  Having examined it with the microscope, it gradually separated into filaments and large globules, several of which were attached to each other like a string of beads; but I could discover no distinct motion; only, as the matter dissolved, it formed a kind of current, by which the filaments and globules were carried down to one side of the glass.  I waited till the matter should become more fluid; but I was disappointed; for, after liquifying [sic] a little, it dried up, and I could observe nothing farther than what I have already described.  I then added water to it, but without success; for the water seemed not to penetrate or dilute the matter. 

 

EXPER. XVIII.

 

            I opened another rabbit, and found only a small quantity of seminal matter, which had hardly [164] any of the yellow colour, and was more fluid than the former.  As the quantity was very small, I was apprehensive lest it should dry too suddenly; I therefore instantly mixed it with water, and could perceive in it neither the filaments nor the strings of beads that I had observed in the other; but I discovered the large globules, and farther remarked, that they had a kind of trembling restless motion.  They had also a progressive motion; but it was very slow:  Some of them moved round others, and most of them appeared to turn round their centres.  I could proceed no farther in my observations, because the liquor dried suddenly up.

 

EXPER. XIX.

 

            Having dissected another rabbit, that had been placed in the same circumstances, I found no seminal liquor; but, in the seminal vessels of another, I found nearly as much congealed matter as in Exper. XVII.  I examined this matter without discovering any thing.  I therefore took the whole, and, adding to it a double quantity of water, shook the mixture violently in a glass.  I then left it to settle for ten minutes; after which I examined a drop taken from the surface, and perceived the large globules formerly mentioned; but they were few in number, and perfectly detached from one another.  They moved [165] towards each other; but this motion was so slow, as to be hardly perceptible.  Two or three hours after, the globules seemed to be diminished in size; their motion was more sensible; and they turned upon their centres.  Though their trembling was more apparent than their progressive motion; yet they plainly changed places in an irregular manner, with respect to each other.  In six or seven hours, the globules were become smaller, and their activity was greater. Their number appeared to be great, and all their motions were sensible.  Next day there was a prodigious multitude of moving globules, and they were at least three times less than at first.  I continued my observations for eight days, and I perceived that several of the globules joined; and, though all motion ceased after this union, it appeared only to be superficial and accidental.  Some of them were larger, and others less; though most of them were spherical, some of them were oval, and others cylindrical.  The largest were most transparent; and the smallest were almost black.  This difference could proceed from no accident in the light; for they were always of the same colour, whatever was their situation:  The motion of the small globules was likewise more rapid.  The whole gradually diminished in size, so that, on the eight [sic] day they were so small that it was with the utmost difficulty I could distinguish them, and at last they totally disappeared. [166]

 

EXPER. XX.

 

            In fine, having, with great difficulty, procured the seminal liquor of an other rabbit, in the very state in which it is conveyed into the female, I remarked, that it was much more fluid than that which was extracted from the seminal vessels; and the phaenomena it presented were also very different:  For, in this liquor there were moving globules, filaments without motion, and a kind of globules with tails or threads, similar to those in the seminal fluid of man and of the dog, only these last appeared to less, and more active [Pl. III. fig. 17.].  They traversed, in an instant, the field of the microscope:  Their tails seemed to be much shorter than those of other spermatic animals; and I acknowledge, that I was uncertain whether some of the these tails were not deceptions occasioned by the track of the globules in the liquor; for they moved with such rapidity, that I could hardly observe them; and besides, the liquor, though sufficiently fluid, dried very suddenly.

 

EXPER. XXI.

 

            Having procured, at different times, the testicles and seminal vessels of 12 or 13 rams, recently after they were killed, I could not find, [167] either in the epidydimis or seminal vessels, a quantity of semen sufficient for observation.  In the small drops I could collect, I found nothing but globules without motion.  As these experiments were made in March, I imagined that, by repeating them in October, which is the time of rutting, I might find more liquor in the vessels.  I cut several testicles in two longitudinally, and having collected a small drop of liquor, I still could perceive nothing but motionless globules of different sizes.

 

EXPER. XXII.

 

            I took three testicles of three different rams, cut them into four parts, and put each of them into a glass-vessel, with as much water as was sufficient to cover them, and then shut the vessels so close as to exclude the air.  I allowed the testicles to infuse during four days; after which, I examined the liquor in each glass with the microscope, and found the whole full of moving bodies, most of which were oval, and some of them globular.  They were equally large, and greatly resembled those described in Exper. VIII.  Their motion was not rapid, but equal, uniform, and in all directions.  In each liquor, the moving bodies were nearly of the same size; but, in the one they were larger, in the other less, and, in the third, still more minute:  They had no [168] tails; neither were there, in the liquor, any threads or filaments.  They often changed their figures, and seemed successively to cast their skin or outer covering.  They daily became smaller, and, on the 16th day, they were so small as scarcely to be visible.

 

EXPER. XXIII.

 

            In the following October, I opened a ram, and found a great quantity of seminal liquor in the epidydimis.  Having examined it with the microscope, I saw such an innumerable multitude of moving bodies, that the liquor seemed to be entirely composed of them.  As the liquor was too thick, I diluted it with water; but I was astonished to find, that the water had stopped all motion in the bodies; though I saw them distinctly in the liquor, they were all at absolute rest.  Having frequently repeated the same experiment, I discovered, that cold water, which diluted the seminal liquors of other animals, made that of the ram coagulate.

 

EXPER. XXIV.

 

            I then opened another ram, and, to prevent the liquor from coagulating by cold, I left the parts of generation in the body of the animal, [169] which was covered with warm cloths.  This precaution afforded me an opportunity of examining with ease the seminal liquor of many rams in its fluid state.  It was filled with an infinite number of oblong moving bodies, [pl. III. fig. 18.] which run about in every direction.  But, whenever the liquor cooled, all motion instantly ceased; so that I could never observe the same drop above a minute or two.  When I diluted the liquor with warm water, t he bodies continued to move for three or four minutes.  The moving bodies were so numerous, that, though the liquor was diluted, almost all of them touched each other.  They were all of the same size and figure.  None of them had tails.  Their motion was not rapid; and, when the liquor began to coagulate, they suffered no change in their form.

 

EXPER. XXV.

 

            As I was persuaded, both by my theory, and the experiments made by others upon this subject, that the female, as well as the male, possessed a prolific seminal fluid; and, as I had no doubt but that the glandular bodies of the testicles, where prejudiced anatomists had in vain searched for the egg, were the reservoirs of this fluid; I purchased several dogs and bitches, and male and female rabbits, which were kept sepa- [170] rate from each other:  And, that I might have an object to compare with the female fluid, I again examined the seminal liquor of a dog, which had been emitted in the natural manner.  I found the moving bodies in the same state and attended with the same circumstances as formerly [pl. IV. Fig. 19].

 

EXPER. XXVI.

 

            A live bitch was next dissected, which had been four or five days in season, without having any communication with the male.  The testicles were as large as filberds [sic].  On one of them I found a red prominent glandular body of the size of a pea, which had a perfect resemblance to a little nipple, with a visible fissure, that had two lips, one of which was more prominent than the other.  Having opened this fissure, a liquor distilled from it, which we collected for examination.  The testicles were then returned into the body of the animal, which was still alive, in order to preserve them from cold.  I then examined this liquor with the microscope, and had the satisfaction of perceiving, at the first glance, moving bodies with tails, exactly similar to those which we had observed in the seminal fluid of the dog [pl. IV. Fig. 20.].  Messrs Needham and Daubenton, who were present, were so struck with this resemblance, that they could not [171] be persuaded that the spermatic animals were not the very same; and they imagined that I had forgotten to change the object-glass, or rather, that the same pick-tooth with which the drops of the female fluid were collected, had also been employed in collecting those of the male.  Mr Needham, therefore, changed both the object-glass and the pick-tooth, and took a fresh drop from the fissure of the glandular body, and examined it first with his own eyes.  He again saw the very same moving bodies, and was fully convinced, not only of the existence of spermatic animals in the seminal fluid of the female, but also of their resemblance to those in the semen of the male.  We repeated the experiment with fresh drops no less than ten times, in all of which the phaenomena were exactly the same.

 

EXPER. XXVII.

 

            Having then examined the other testicle, I found an unripe glandular body, which was smaller, and less red than the former, and had no fissure; but, after opening it with a scalpel, I found no liquor.  Upon the external surface of this testicle, there were some lymphatic vesicles.  I pierced one of them with a lancet, and there issued a clear liquor, to which I immediately applied the microscope.  But it contained nothing similar to what we discovered in [172] [PLATE V HERE] that of the glandular body.  It was a transparent liquor, composed of very small globules, without any motion.  After repeating this experiment several times, I was convinced, that the liquor in the vesicles is only a species of lymph, which contains nothing animated or similar to what we perceive in the female semen, which is secreted and matured in the glandular bodies. 

 

EXPER. XXVIII.

 

            Some time after, another bitch was opened, which had been seven or eight days in season, and had not received the male.  I examined the testicles, and upon each I found a glandular body in full perfection.  The first was half open, and had a canal which penetrated the testicle, and was full of seminal fluid; the second was larger and more prominent, and the fissure or canal that contained the fluid was below the nipple, which protruded outward.  I took the liquor out of both the glandular bodies, and, on comparison, found them entirely similar.  This seminal liquor of the female is equally fluid with that of the male. After examining the liquors extracted from each testicle, I found in them the very same moving bodies [pl. IV. fig. 21].  I perceived at leisure the same phaenomena that I had observed in the seminal liquor of the other bitch; I saw several globules which moved with [173] great rapidity, which endeavoured to disengage themselves from the mucilage that surrounded them, and which dragged tails or threads after them.  Their number was equally great with that in the male semen.

 

EXPER. XXIX.

 

            I squeezed the whole liquor out of these two glandular bodies, and put it into the glass of a watch.  The quantity was sufficient to serve for four or five hours observation.  I remarked that it deposited a kind of sediment, or at least began to thicken.  I took a drop of the thickest part of the liquor, and having examined it, I discovered that the mucilaginous part of the semen was condensed, and formed a kind of net-work.  From the anterior edge of this net-work, there issued a current of globules which moved with great rapidity [Pl. IV. fig. 22.].  These globules were extremely active and lively, and they appeared to be divested of their mucilaginous coverings, and of their tails.  This stream of globules resembled the motion of the blood in the veins; for they seemed not only to be animated, but to be pushed on by some common force, which obliged them to follow each other in troops or rows.  From this experiment, and from the 11th and 12th, I concluded, that, when the fluid begins to coagulate or grow thick, the ac- [174] tive globules break their mucilaginous covering, and escape at that side where the liquor is most fluid.  They had no threads or tails, and most of them were oval, and seemed to be flat below; for they had no rolling motion.

 

EXPER. XXX.

 

            I opened the horns of the uterus longitudinally, and having squeezed a little liquor out of them, I found it exhibited precisely the same phaenomena with that obtained from the glandular bodies.  These glandular bodies are so situated, that they can easily pour their liquor upon the horns of the uterus:  And I am persuaded that, during the whole season of love, there is a perpetual distillation of this liquor from the glandular bodies into the horns of the uterus; that this distillation continues till the glandular bodies be entirely emptied; and that they are gradually effaced, leaving only behind them a small reddish cicatrice [sic] on the external surface of the testicle. 

 

EXPER. XXXI.

 

            I missed the seminal liquor of the female with an equal portion of that of the male, which was recently emitted; but the moving bodies, and every circumstance, were so entirely the same, [175] that I could make no distinction between those of the male and those of the female.

 

EXPER. XXXII.

 

            Having dissected a young bitch that had never been in season, I discovered on one of the testicles only, a small solid protuberance, which I imagined to be the rudiments of a glandular body. The surface of the testicles was smooth and uniform, and it was with difficulty I could see the lymphatic vesicles, till the membranes which cover the testicles were removed.  The small quantity of liquor that was squeezed from the testicles contained no moving bodies.

 

EXPER. XXXIII.

 

            In another bitch still younger, there was no appearance of glandular bodies on the testicles; their surface was white and perfectly smooth.  Some small; vesicles were discovered; but they seemed to contain no liquor.  I compared these female testicles with those of a male of the same age, and found that their internal texture, which was fleshy, was nearly of the same nature.  [176]

 

EXPER. XXXIV.

 

            I procured the uterus of a cow that had been recently killed.  It was brought to me in a basket, wrapped in warm cloths, along with a live rabbit, to preserve it from cooling.  The testicles were as large as a small hen’s egg; on one of them was a glandular body of the size of a pea, which protruded from the testicle like a little nipple:  but it had no fissure or external aperture.  It was so firm and hard, that I could press no liquor out of it with my fingers. Before cutting this testicle, I observed two other glandular bodies at a distance from each other.  They were very small, and of a whitish yellow colour; but the large one, which seemed to have pierced the membrane of the testicle, was as red as a rose.  I examined this last with great attention; but could discover no liquor; from which I concluded, that it was still far from being mature.

 

EXPER. XXXV.

 

            In the other testicle, there were no glandular bodies which had yet pierced the membrane that covers the testicle.  Two small ones only began to appear under the membrane.  I opened them both; but procured no liquor from them.  They were hard bodies, with a tincture of yellow.  [177]  On each testicle there wee four or five lymphatic vesicles; they were full of liquor.  When examined with the microscope, some small globules appeared; but there was not in them the least vestige of motion.  I observed this liquor, from time to time, for two days, without discovering any thing new.

 

EXPER. XXXVI.

 

            I had to other uteri conveyed to me in the same manner.  The one belonged to a young cow that had never brought forth; the other to a cow which, though not old, had had several young.  I first examined the testicles of the latter, and found, upon one of them, a glandular body as large as a cherry.  I perceived three holes into which bristles might be introduced.  Having pressed the body with my fingers, a small quantity of liquor issued out, which I examined, and had the pleasure of seeing moving bodies, [Pl. IV. fig. 22.], but different from what I had observed in other seminal fluids.  These globules were small and obscure:  Their progressive motion, though distinct, was very slow.  The liquor was not thick:  The moving globules had no appearance of threads or tails, and they were not all in motion.  These are all the observations I could make on this liquor; for, though I again squeezed the glandular body, I [178] could not obtain any more liquor than was unmixed with blood.  The moving bodies were at least a fourth part less than the globules of the blood. 

 

EXPER. XXXVII.

 

            This glandular body was situated at one extremity of the testicle, near the horn of the uterus; and the liquor which it distilled must have fallen upon that horn, I found no liquor.  I then opened the testicle longitudinally, and, though its cavity was considerable, it contained no fluid.  At some distance from the large glandular body, there was a small one of the same kind, about the size of a lentil.  Two cicatrices, or little pits, also appeared; they were of a deep red colour, and were the relicts [sic] of old glandular bodies which had been obliterated.  Having next examined the other testicle of the same cow, I discovered four cicatrices and three glandular bodies, the most advanced of which was of a red flesh-colour, and exceeded not the size of a pea.  It was solid, without any aperture, and contained no liquor.  The other two were much smaller and harder; and their colour was a kind of orange.  The lymphatic vesicles were full of a clear liquid; but nothing living appeared in it.  [179]

 

EXPER. XXXVIII.

 

            I then inspected the testicles of the young cow, which had never brought forth.  They were rather larger than those of the other cow.  But, what is not less remarkable than true, there was not a single cicatrice on either of them.  A number of lymphatic vesicles appeared on one of the testicles; but there was no vestige of glandular bodies.  Upon the other testicle, I could not discern the rudiments of two glandular bodies, one just beginning to spring up, the other as large as a small pea.  There are also many vesicles, which appeared, after being pierced with a lancet, to contain nothing.  The glandular bodies, when opened, gave forth nothing but blood.

 

EXPER. XXXIX.

 

            I cut each testicle of both cows into four parts, and, having put them into separate vials, I poured as much water upon them as was just sufficient to cover them; and, after corking the vials close, I allowed them to infuse for six days.  I then examined the infusions with the microscope, and saw an amazing number of moving globules, [Pl. IV. fig. 23.].  In all the infusions, the globules were extremely small, but very [180] active, moving with rapidity round their centres, and in all directions.  I observed them, from time to time, during three days, and they always became smaller and smaller, till they totally disappeared on the third day.

 

EXPER. XL.

 

            I procured the uteri of three other cows; and I first searched the testicles, in order to discover if there were any mature glandular bodies.  In two of the uteri I found only small glandular bodies on the testicles.  I was not informed whether the cows had ever brought forth; but it is probable that they had often been in season; for a number of cicatrices appeared on their testicles.  On one of the testicles of the third cow, I observed a glandular body as large as a cherry, and very red; it was much swelled, and seemed to be perfectly ripe.  I pressed the nipple, which was perforated by a hole, with my fingers, and a considerable quantity of liquor issued out.  In this liquor, I found moving bodies [Pl. IV. fig. 24] perfectly similar to those described in Exper. XXXVI.  Their number was indeed greater, and their progressive motion was quicker; they seemed to be somewhat longer; and, having observed them for a long time, I perceived that they grew longer, and changed their figure.  I then introduced a fine probe into the small [181] aperture of the glandular body; and, having cut along the probe as a directory, I found that the cavity was filled with a liquid matter.  This liquor, when examined with the microscope, presented the same phaenomena, the same moving bodies as in Exper. XXXVI.  But I could discover in none of them either the filaments or tails.  The liquor of the vesicles was still transparent, and contained nothing like life or motion.

 

EXPER. XLI.

 

            The uteri of several other cows were brought me at different times.  In the testicles of some of them, there were glandular bodies almost ripe; in those of others, they were in different states of growth; and I perceived nothing new or uncommon, excepting that I discovered, in the testicles of two of them, glandular bodies in a decayed state, the base of one of which was as large as the circumference of a cherry.  The extremity of the nipple was soft and withered:  The two small holes through which the fluid had issued were still visible.  I introduced a small bristle into them; but there was no liquor either in the canal, or in the internal cavity, which could still be distinguished.  The extinction of the glandular bodies, therefore, commences at the most external part, or extremity of the nipple.  They first diminish in height, and then [182] [PLATE VI HERE] in breadth, as I had an opportunity of observing in another testicle, where there was a glandular body diminished about three fourths. 

 

EXPER. XLII.

 

             As the testicles of female rabbits, as well as their glandular bodies, are very minute, I could make no experiments on their seminal liquor.  I only discovered, that the testicles of different females are in different states; and that I never say any of them which exactly resembled De Graaf’s figures.

 

EXPER. XLIII.

 

            On the testicles of some cows, I found a species of bladders or vesicles, which are called hydatides, [sic] by anatomists.  I observed some of them large and others small; and they were attached to the testicle by a kind of pedicle.  I examined the liquor they contained; but it was transparent, homogeneous, and every way similar to the liquor in the vesicles.  It had no globular or moving particles.

 

EXPER. XLIV.

 

            At this time, I made some experiments upon oister-water [sic], upon water in which pepper had [183] been boiled, upon water in which pepper had been simply infused, and upon water in which pink-seeds were infused.  The bottles containing all these infusions were exactly corked.  At the end of two days, I saw, in the oister-water, a vast quantity of oval and globular bodies, which seemed to swim like fishes in a pond, and had every appearance of being real animals.  They had no members that could be discovered, and no tails.  They were transparent, and pretty large; I saw them change their figures; they became gradually smaller and smaller during the seven or eight days that they subsisted; and, lastly, along with Mr Needham, I saw animalcules so very similar, in an infusion of the jelly of roasted veal, which had likewise been close corked, that I am persuaded they are not true animals, agreeable to the common acceptation of that term, as shall afterwards be fully explained.

 

            The infusion of pink-seeds was crowded with innumerable moving globules, which appeared to be equally animated with those in the seminal liquors and in infusions of the flesh of animals.  At first they were pretty large, and moved with great rapidity in every possible direction.  They continued in this state during three weeks, and gradually diminished in size till their minuteness rendered them invisible.

 

            The same phaenomenon took place in the infusions of pepper; but the moving bodies did [184] not appear so early as in the other infusions, and their appearance was later in the infusion of pepper that was not boiled.  I then began to suspect that what is called fermentation, might be owing to the motion of these organic particles in animal and vegetable substances.  To discover if there was any similarity between this species of fermentation, and that excited by mineral substances, I applied to the microscope a little limestone powder, and poured upon it a drop of aquafortis.  But the phaenomena were totally different.  Large bubbles rose to the surface, and instantly darkened the lens of the microscope; when the gross parts were dissolved, every thing remained at rest, and nothing appeared which had the smallest analogy to what we perceive in the infusions of animal or vegetable bodies.

 

EXPER. XLV.

 

            I examined the seminal liquor in the mils of different fishes, extracted while the animals were alive, and I observed a vast quantity of obscure moving globules.  I then squeezed with my fingers the aperture in the bellies of fishes through which they emit this liquor, and, in the drops which I procured, I saw great multitudes of the same moving globules, which were almost black, and very small.  [185]

 

EXPER. XLVI.

 

            Before I conclude this chapter, I shall relate the experiments of Mr Needham upon the semen of a species of cuttle-fish, called the Calmar.  This acute observer, having examined the spermatic animals in the milts of different fishes, found them of an uncommon magnitude in the milt of the calmar.  To the naked eye, they were from three to four lines in length.  During a whole summer, while he dissected calmars at Lisbon, he could find no appearance of a milt, or of any reservoir destined to receive the seminal liquor of that fish; and it was the middle of December before he could perceive the first vestiges of a new vessel filled with a milty [sic] juice.  This reservoir, and the juice it contained, gradually increased.  In examining this seminal liquor with the microscope, he saw nothing in it but small opaque globules swimming in a kind of serous matter, without any appearance of life.  But, some time after, he discovered in the milt of another calmar, organic bodies completely formed, which resembled spiral springs, [a, b, Pl. I. fig. 5.] inclosed in a transparent case.  These springs were equally perfect at the first observation as afterwards; only they, in time, contracted themselves, and formed a kind of screw.  The head of the case is a species of valve [186] which opens outward, and through which every thing within may be forced out.  It contains, besides, another valve b, a little barrel, c, and a spongy substance d, e.  Thus the whole machine consists of an outer, transparent, cartilaginous case, a, fig. 2. the superior extremity of which is terminated by a round head, formed by the case itself, and performs the office of a valve.  This external case contains a transparent tube, which includes the spring, a piston or valve, a little barrel, and a spongy substance. The skrew [sic] occupies the superior part of the tube and case, the piston and barrel are situated in the middle, and the spongy substance occupies the inferior part.  These machines pump the liquor of the milt; the spongy substance is full of this liquor; and, before the animal spawns, the whole milt is only a congeries of these organic bodies, which have absolutely pumped up and dried the milty liquor.  Whenever these small machines are taken from the body of the animal, and put among water, or exposed to the air, they begin to act [Pl. V. fig. 2. and 3.]; the spring mounts up, and is followed by; the piston, the barrel, and the spongy substance which contains the liquor:  And, as soon as the spring and the tube in which it is contained begin to issue out of the case, the spring plaits, and the whole internal apparatus moves, till the spring, the piston, and the barrel have entirely escaped from the case.  When this is effected, all the rest instantly follow, and [187] the milty liquor, which had been pumped, and was confined in the spongy substance, runs out through the barrel.

 

            As this phaenomenon is extremely singular, and incontestibly [sic] proves that the moving bodies in the milt of the calmar are not real animals, but simple machines, a species of pumps, I shall here transcribe Mr Needham’s own account of the matter:

 

            “When the small machines,”* says he, “have come to their full maturity, several of them act as soon as they are exposed to the air.  Most of them, however, may be commodiously viewed by the microscope before their action commences; and, even before they act, it is necessary to moisten with a drop of water the superior extremity of the external case, which then begins to expand, while the two slender ligaments that issue out of the case are twisted and contorted in different ways.  At the same time, the screw rises slowly, and the spirals at its superior end approach each other, and act against the top of the case, those which are lower seeming to be continually followed by others that issue from the piston; I say, that they seem to follow; because I believe it to be only a deception produced by the motion of the screw.  The piston and barrel likewise move in the same direction; and the inferior [188] part, which contains the semen, extends in length, and, at the same time, moves towards the top of the case, which is apparent by the vacuity left at the bottom.  As soon as the screw, with the tube in which it is inclosed, begins to appear out of the case, it twists, because it is constrained by the two ligaments.  The whole internal apparatus continues to move gradually and slowly till the screw, the piston, and the barrel, have entirely escaped.  When that happens, the remainder issues instantaneously.  The piston, b [Pl. V. fig. 2.]. separates from the barrel a; the ligament, which is under the barrel, swells and acquires a diameter equal to that of the spongy part which succeeds it:  This, though much broader than when in the case, become also five times longer than formerly. The tube, which included the whole, contracts in the middle, and forms two knots or joints, d, e, [Pl. V. fig. 2. and 3.], distant about one third of it s length from each extremity. Then the semen escapes by the barrel e, [fig. 2.].  It is composed of small opaque globules, which swim in a serous matter, without discovering any signs of life, and are precisely the same as I perceived them to be when diffused through the reservoir of the milt.  In the figure, the part comprehended between the two joints d, e, appear to be fringed.  When examined attentively, this appearance seems to be occasioned by the spon- [189] gy substance within the tube being broken and divided into portions nearly equal.  The following phaenomena will clearly prove that this is the case.

 

            “It sometimes happens, that the screw and the tube break precisely above the piston b, which remains in the barrel e, [fig. 3.].  Then the tube instantly shuts; and, by contracting, assumes a conical figure above the extremity of the screw, f.  This is a demonstration that it is there very elastic; and the manner in which it accommodates its figure to that of the substance which includes it, when the latter undergoes the smallest change, proves that it is every where equally elastic.”

 

            M. Needham hence concludes, that it is natural to imagine that the total action of this machine is occasioned by the spring of the screw.  But, unfortunately, he proves, by several experiments, that the screw is acted upon by a power residing in the spongy part:  As soon as the screw is separated from the rest of the machine, it ceases to act, and loses all motion. The author draws the following conclusion from this singular phaenomenon.

 

            “If I had seen,” says he, “these pretended animalcules in the semen of living animals, I should, perhaps, have been able to ascertain whether they are really animated beings, or only prodigiously small machines, which correspond in miniature to the large vessel of the calmar.”  [190] [PLATE VII HERE]

 

            From this and other analogies, Mr Needham concludes, that the spermatic worms of other animals, it is reasonable to think, are only organic bodies; a species of machines similar those of the calmar, which act at different times; for, says he, if we suppose that, of the prodigious number of spermatic animalcules which appear in the field of the microscope, only a few thousands act at a time, this will be sufficient to make us believe the whole to be alive.  If it be farther supposed, he adds, that the motion of each animalcule lasts, like that of the calmar machines, about half a minute; in this case, the successive action of the small machines would continue for a considerable time, and the animalcules would die one after another.  Besides, why should the semen of the calmar alone contain machines, while that of all other animals contain real living animalcules?  Here the analogy is so strong as to be almost irresistible.  Mr Needham farther remarks, that even Leeuwenhoek’s experiments seem to indicate that the spermatic animals have a great resemblance to the organic bodies in the semen of the calmar.  Speaking of the semen of the cod, Leeuwenhoek remarks, that he imagined the oval bodies to be animalcules burst and distended, because they were four times larger than when alive.  And, in another place, he observes of the semen of the dog, that the animalcules often changed [191] their figure, especially when the liquor began to evaporate.*

 

            On all these accounts, Mr Needham conjectured that the pretended spermatic animals were only a kind of natural machines, bodies much more simply organized than those of real animals.  I examined the machines of the calmar along with him, and the reader may be assured that his description of them is both exact and faithful.  His experiments, therefore, demonstrate, that the seminal fluid consists of particles in quest of organization; that, in fact, it produces organized bodies; but that these bodies are not animals, nor similar to the individual which produces them.  It is, indeed, probable, that these organized bodies are only a kind of instruments [sic] for perfecting the semen, and bestowing on it an active force; and that it is by their internal action that they intimately penetrate the seminal fluid of the female.  [192

Notes

 

*  Published in the year 1745 [back to page 149]

 

+  Here M. de Buffon mentions the advantages of the double microscope, and some precautions necessary in the management of it, which, not that the instrument is well known, and much improved since the author wrote, it is unnecessary to translate [Smellie’s note.  Back to page 149]. 

 

*  Needham’s New Discoveries made with the Microscope, ch. 6. p. 53 [back to page 188].

* See Leeuwenh. Arc. nat. p. 306. 309. and 319 [back to page 192].