490 ON GENERATION. 



are not unlike crabs' eyes, and I have called them by this name -, 

 but they are smaller, like pendulous warts, glandular and white, 

 sticking within the coats of the uterus, and somewhat excavated 

 towards the conception; otherwise than in the deer, conse- 

 quently, in which the caruncles corresponding to these rather 

 project towards the embryo. These caruncles are gorged with 

 blood, and their inner surface, where they regard the conception, 

 is perceived to be beset with black sanguineous points. The 

 umbilical vessels of the embryo were not yet connected with 

 these caruncles, nor did the conception itself adhere to the 

 uterus. 



I find nothing of an allantois, of which something has been 

 said as a tunic distinct from the chorion, in the conception of 

 the ewe. At a later period, indeed, when the embryo is larger, 

 when the ovum or conception has contracted adhesions with 

 the uterus, and the umbilical vessels have penetrated the carun- 

 cles, the chorion extends further, and at its extremities on 

 either side, and as it were in a couple of appendices, there is a 

 certain fluid of a yellow colour, which you might call excre- 

 mentitious, kept separate and distinct. 



The human conception scarcely differs in any respect from 

 an egg during the first months of pregnancy. I have observed 

 a clear fluid, like the more liquid white of an egg, to be in- 

 cluded within an extremely delicate membrane. At this time 

 the placenta had not yet appeared, and the entire conception 

 was of the size of a pigeon's, or perhaps a pheasant's egg. 

 The embryo itself, of the length of the little finger nail, and 

 having the form of a small frog, was conspicuous enough. The 

 body was broad, the oral aperture widely cleft, the legs and arms 

 like the stalks of flowers just risen above the ground, the occiput 

 prominent, or rather forming a vesicle appended to the rest of 

 the head, such as we have described the rudiments of the future 

 cerebellum in the chick. 



In another human conception of about the fiftieth day, the 

 ovum was as large as a hen's or a turkey's egg. The embryo 

 was as long as a large bean, the head of very large relative 

 dimensions, and dominated by the cerebellum as by a kind of 

 crest. The brain itself was of the consistence of curdled milk. 

 Instead of a cranium there was a coriaceous membrane, in 

 some places cartilaginous, and divided down the forehead to 



