SECT. 3] AND EIGHTEENTH CENTURIES 139 



hatch egges, which they did dayly open to discerne the progress 

 and way of generation". Aubrey mentions a conversation he had with 

 a sow-gelder, a countryman of Httle learning, but much practical 

 experience and wisdom, who told him that he had met Dr Harvey, 

 who had conversed with him for two or three hours, and "if he had 

 been", the man remarked, "as stiff as some of our starched and 

 formall doctors, he had known no more than they". Harvey seems 

 also to have learnt all he could from the keepers of King Charles' 

 forests, as several passages in his book show. Nor was the King's own 

 interest lacking. "I saw long since a foetus", he says, "the magnitude 

 of a peasecod cut out of the uterus of a doe, which was complete 

 in all its members & I showed this pretty spectacle to our late King 

 and Queen. It did swim, trim and perfect, in such a kinde of white, 

 most transparent and crystalline moysture (as if it had been treasured 

 up in some most clear glassie receptacle) about the bignesse of a 

 pigeon's Ggge, and was invested with its proper coat." And, again — 

 "My Royal Master, whose Physitian I was, was himself much 

 delighted in this kinde of curiosity, being many times pleased to be 

 an eye-witness, and to assert my new inventions". 



Harvey's book is composed of seventy-two exercitations, which 

 may be divided up for convenience into five divisions. In Nos. i 

 to 10 he speaks of the anatomy and physiology of the genital organs 

 of the fowl, and the manner of production of eggs. Nos. 11 to 13 

 and also Nos. 23 and 36 deal with the hen's egg in detail, describing 

 its parts and their uses, while in Nos. 14 to 23 the process of the 

 "generation of the foetus out of the hen egge'' is described. The 

 greater part of the book, comprising Nos. 25 to 62, as well as Nos. 71 

 and 72, is theoretical, and treats of the embryological theories held 

 by Aristotle on the one hand, and the physicians, following Galen, 

 on the other, instead of which it propounds new views upon the 

 subject. Finally, Nos. 63 to 70, as well as the two appendices^ or 

 "particular discourses", are concerned with embryogenesis in vivi- 

 parous animals, especially in hinds and does. 



It will be best to refer to certain details and main points of interest 

 in Harvey's discussions, before trying to assess his principal contribu- 

 tions to the science as a whole. Harvey is the first, since Aristotle, 

 to refer to the "white yolk" of birds. "For between the yolk", he 

 says, "which is yet in the cluster and that which is in the midst of 

 the eg when it is perfected this is the difference in chief, that though 



