VOL. XXni.3 PHILOSOVHICAL TRANSACTIONS. 669 



and they remained alive for the space of half an hour, after I had squeezed a 

 drop of the seed out of the said vessels. These animalcules appear, both in 

 motion and when they lye still, as if the fore-part of their body was crooked, 

 or circular, abcd, pi. l6, fig. 12, represent one of those animalcules in its 

 full length ; abc is the body, which is seldom quite straight, but the tail mostly 

 folded ; its tail is long, and exceedingly small, which is shown by cd. 



In the fore-part of the bodies of many of those animalcula I discovered a 

 clear bright spot, which was not to be seen in others ; and the tails of such as 

 lay dead were like so many bows, as represented fig. 13, J 4, 15, \6. 



September 17, 1701, about iO o'clock in the morning, I again viewed the 

 semen masculinum of a young cock, which was about 12 weeks old, and had 

 been killed an hour before, where I found the animalcula full of life. I took 

 some of the same seed, about the quantity of a large pin's head, and ordered 

 it so, that very little of the fluid matter could exhale. I observed this matter 

 every hour, and the same evening about 7 o'clock I found the animalcula as 

 lively as ever. But about 8 or g o'clock I could perceive that many of them 

 were dead, and in one place, the space no larger than a grain of sand, there 

 were great shoals of them living ; but a little further, and in a place of much 

 the same extent, I could not perceive the least motion in those that lay there. 



September 18, in the morning, about 7 o'clock, and also about noon, I again 

 made my observations of the same-seed, as it lay in a glass tube, as large as a 

 thick pin, but I could see no life in the animalcula ; but when I looked on 

 another part of the same matter, of the size of a large sand grain, and spread 

 very thin on the glass, I saw a great many, very lively and nimble in their mo- 

 tions, but their life and motion dwindled away, till at last I could perceive none; 

 the reason of which I judged to be, that the thin fluid matter was all exhaled 

 from the seed, and that then the animalcula presently die. 



To satisfy myself further in this matter, I took a dead cock, that had been 

 killed and plucked the day before, between the hours of 7 and Q in the morn- 

 ing, and opening the body, I pulled out the guts and stomach, that I might 

 the better come at the vasa seminalia deferentia : I squeezed out of one of the 

 seminal vessels a drop of the seed, and presently setting it before my micro- 

 scope, I could see an infinite number of those animalcula, swimming in legions 

 together, and crossing one another like clouds in a stormy day, and as brisk 

 and lively as if the cock had been newly killed. I put into the boily again that 

 part of the intrails which 1 had taken out, and drew the skin over it, in order 

 to take out a little more of the seed about 6 hours after ; and accordingly at 

 noon I took out a little of the seed, and found the animalcula in it still 

 living. 



