608 PHILOSOPHICAL TRANSACTIONS. [aNNO 1748. 



Levvenhoeck, or any other. The result of these conjectures was, that, orderin 

 a bitch in heat to be strangled, and dissected immediately, they found two of 

 these red excrescences florid and ripe, one on each ovary, these, from their re- 

 spective cavities that ran obliquely under these productions for near an inch in 

 length, furnished a tea spoonful of a thick turbid fluid; and this fluid, observed 

 in the microscope with the most powerful magnifier, after some little time ex- 

 hibited numbers of spermatic animals, in every respect like those hitherto ob- 

 served by other naturalists, animated, and moving spontaneously. Thus was 

 Mr. de Buffbn's conjecture verified in every particular. 



About this time, or some few days after, Mr. de Buffbn in his presence ex- 

 amined several sorts of male semen; and then it was that, for the first time, they 

 fairly saw the spermatic animals enascent. Those kinds which satisfied them in 

 this particular were extremely viscid, and contained in a certain quantity in 

 the crystal of a watch. These precautions are not unnecessary; for if a viscid 

 kind be not chosen, and that in a good quantity together, such as that of stags, 

 &c. or any seed of the least exalted sort, so to term it, as they found some to be 

 more so than others ; it will alter in the atmosphere by an evaporation of its vo- 

 latile parts, which serve to hold it though but gently together, after which it 

 will liquefy, vegetate, ramify into filaments, and these filaments again break 

 into moving globules, especially if the weather be hot, before a small portion 

 can be adjusted to the microscope : by which an observer may easily be imposed 

 on, and think the spermatic animals original and pre-existent, because he could 

 not discern that action which produced them. This deception takes place in all 

 semen of the more exalted kinds, such as particularly the milt offish, when it is 

 in a state of immediate impregnation, and many others: for it is to be observed 

 that the semen of animals is not at all times in an equal state of exaltation; and 

 consequently that some sorts, or even the same at different times, will at some times 

 give the spermatic animals immediately, but at others not so soon, and perhaps 

 not under some hours : which is the reason why they have often been said by 

 naturalists, and even by Lewenhoeck himself, not to have been found on in- 

 spection. By this it will appear, that they had tried many sorts, before they had 

 the good fortune to meet with one, in that exact degree of exaltation necessary 

 to exhibit the whole process of this vegetation; and so may others who shall be 

 desirous of trying these experiments after : yet, when they shall at last have ob- 

 tained a proper subject, one accurate view will be sufficient, and found to give 

 the key to the whole secret. 



When they had seized this favourable opportunity, they saw a small portion 

 of male semen placed on the microscope, first, as it were to develope and liquefy, 

 then shoot out into long filaments, ramify on every side, these open and divide 

 into moving globules, and trailing after them something like long tails ; these 



