VOL. XV.] PHILOSOPHICAL TRANSACTIONS. 203 



judge how many young would next have been brought forth, by the number of 

 red specks in the ovarium, though none of the eggs were to be found in the 

 uterus. He was also of opinion, that the eggs first came down in the uterus, 

 4 days after the female had taken the buck. But it is strange that rabbits 

 should be matured in 30 days, and yet the eggs first be seen in 74 parts of 

 the time. 



In the year 167 s I sent to the Royal Society the draught of one of those 

 numerous animals, which are in the semen of a dog ; noting that they are so 

 small that 1,000,000 are not equal to a coarse sand. I shall here again insert the 

 same figure, that you may see how I imagine these animals came to be round in 

 the uterus. I need not mention how several insects cast their skin, and how 

 tadpoles, as they grow in size, lose their tails, and appear to be frogs. 



In fig. 8, EFGH is one of the animals of the semen of a dog, as I saw it 

 swimming. IKLM, fig. 9, is one of the animals when dead. I have often 

 observed these last animals to change their figure, chiefly when the moisture 

 about is exhaled. When one of these animals has got so far in the womb, that 

 it finds a place fit to nourish it ; then may it suddenly cast off its tail, or its 

 whole outward covering, and remain of an oval form. 



I believe that what is called frigidity in some men, is either a want in them of 

 the animalia seminis, or a weakness in the animals, which renders them unable 

 to live long in the womb. If this be true then, that a foetus is an animal 

 seminis masculi, we may reject the vulgar opinion, that a conception comes to 

 be male or female according to the prevalency of one seed above the other, 

 since the animalia seminis are themselves of both sexes. 



In the beginning of February I received from a butcher, the uterus of a 

 sheep, which had taken the ram they said 1 7 days before. I found in one of the 

 cornua a small body wrapped up in membranes of a red fleshy colour. But 

 being not able to distinguish its figure, though I put it in a glass tube about the 

 thickness of a goose quill, together with oil of turpentine; I took it out of the 

 glass again, and as it lay round, I gently stretched it out in length, and then I 

 plainly saw the back bone, with blood vessels lying near it, and sending forth 

 several branches, also in two distinct places the medulla spinalis lying in the 

 back-bone. And in the head, I saw not only the maxillae, but the muscles that 

 covered them, and the vessels lying in them, though they were not yet red 

 and looked like sinews. Likewise the brain, and the small blood vessels there- 

 in ; the eyes about the size of a coarse sand, but as clear as crystal, I opened 

 the belly, and took out several pieces of the bowels, which were transparent, 

 and about the size of a small hair. I saw several strings of flesh, which I took 



D D 2 



