6o EMBRYOLOGY IN ANTIQUITY [pt. ii 



animal grows great, being nourished by a multitude of similar 

 particles." This is as near as Plato gets to embryological speculation. 

 His description has a causal ring about it, which is in some contrast 

 with the predominantly teleological tone of the rest of his writings ; 

 for instance, only a few pages earlier he has been speaking of the 

 hair as having been arranged by God as "a shade in summer and a 

 shelter in winter". It is also true that Plato may have said more 

 about the embryo than appears in the dialogues. Plutarch mentions 

 various speculations about sterility, and adds, "Plato directly pro- 

 nounceth that the foetus is a living creature, for that it moveth and 

 is fed within the bellie of the mother". 



But all this was only the slightest prelude to the work of Plato's 

 pupil, Aristotle. Aristotle's main embryological book was that 

 entitled Trepl ^mcov yeveaeco'i, On the Generation of Animals, but embryo- 

 logical data appear in irepl ^axop, The History of Animals, irepl ^wmv 

 fjLopicov, On the Parts of Animals, Trepl dva7rvofj<i, On Respiration, and 

 Trepl ^Mcov Ktvrjcr€(o<i, On the Motion of Animals. All these were written 

 in the last three-quarters of the fourth century B.C. 



With Aristotle, general or comparative biology came into its own. 

 That almost inexhaustible profusion of living shapes which had not 

 attracted the attention of the earlier Ionian and Italo-Sicilian philo- 

 sophers, which had been passed over silently by Socrates and Plato, 

 intent as ever upon ethical problems, but which had been for cen- 

 turies the inspiration of the vase-painters and other craftsmen 

 {(^coypdcjioL), was now for the first time exhaustively studied and 

 reduced to some sort of order. The Hippocratic school with their 

 "Coan classification of animals", which Burckhardt has discussed, 

 had indeed made a beginning, but no more. It was Aristotle who 

 was the first curator of the animal world, and this comparative out- 

 look colours his embryology, giving it, on the whole, a morphological 

 rather than a physiological character. 



The question of Aristotle's practical achievements in embryology 

 is interesting, and has been discussed by Ogle. There is no doubt 

 that he diligently followed the advice of the author of the Hippocratic 

 treatise on generation and opened fowl's eggs at different stages 

 during their development, but he learnt much more than the un- 

 known Hippocratic embryologist did from them. It is also clear 

 that he dissected and examined all kinds of animal embryos, mam- 

 malian and cold-blooded. The uncertain point is whether he also 



