XXXVIII. I then examined the testicles of the young cow which had not calved, which, notwithstanding, were something larger than the other, but it is true there were no cicatrices on either of them; the one was smooth and very white, and a number of lymphatic vesicles were sprinkled about it, but there was not the least mark of a glandular body. On the other testicle I perceived the marks of two glandular substances, the one had just began to grow, and the other was the size of a pea; there was also a great number of lymphatic vesicles, which I pierced with a lancet, but the liquor did not contain any thing; having pierced the two small glandular bodies some blood alone issued thereout. XXXIX. I divided each testicle of both cows into four parts, and, having put them into separate phials, I poured as much water on as would cover them, and after having closely corked them up, I suffered to infuse for six days; I then examined these infusions, and discovered an innumerable quantity of living moving bodies (_fig. 12._); they were all, in these infusions, extremely small, moved with a surprising rapidity in all directions. I observed them for three days, and they always appeared to diminish, till at last, on the third day, they entirely disappeared. XL. The following day they brought to me the genital parts of three more cows. I immediately searched the testicles to find one where the glandular substance was in perfect maturity; but in two of them I only discovered some growing glandular substances on the testicles. I could not learn whether these cows had calved or not, but there was a great appearance they had all been in season, for there were a great number of cicatrices on all these testicles. In the third I found a testicle, on which was a glandular substance, as thick and as red as a cherry; it was inflamed, and seemed to be in full maturity. Its extremity was a nipple, with a small hole; I pressed it a little between my fingers, and a quantity of liquor issued out. I found in this liquor moving globules, exactly like those in the liquor pressed from the glandular body of the other cow, I have before spoken of in experiment XXXVI. They appeared to be more numerous, their progressive motions were not so slow, and their size larger. Having observed them for some time I perceived some to lengthen and change their form. I then introduced a very fine instrument into the little hole of the glandular substance, and having opened it I found the internal cavity replete with liquor; this liquor offered me the same phenomena, and the same moving globules, as I before observed in experiment XXXVI. with either filaments, threads, or tails attached to them. The liquor of the vesicle presented me with nothing more than nearly a transparent matter, which did not contain one moving thing.