SECT, i] EMBRYOLOGY IN ANTIQUITY 69 



qualities are found in the parts that have life and soul, may be caused 

 by mere heat and cold yet, when we come to the principle, Xoyof, 

 in virtue of which flesh is flesh and bone is bone, that is no longer so ; 

 what makes them is the movement set up by the male parent, who 

 is in actuality what that out of which the offspring is made is in 

 potentiaUty . This is what we find in the products of art ; heat and 

 cold may make the iron soft or hard, but what makes a sword is the 

 movement of the tools employed, this movement containing the 

 principle of the art. For the art is the starting-point and form of 

 the product; only it exists in something else (i.e. potentially in the 

 mind of the artist), whereas the movement of nature exists in the 

 product itself, issuing from another Nature (i.e. the parent) which 

 has the form in actuaHty." 



Thus Aristotle, evidently influenced by his doctrine of "form" and 

 "matter", decided against preformation and pictured at one and 

 the same time the unformed catamenia as containing a kind of clock- 

 work m.echanism which, once set in motion, would inevitably produce 

 the finished embryo, and also as an inchoate substance on which 

 the seminal essence should act like a swordmaker producing a sword 

 according to the motions of a natural art. These two ideas are not 

 completely reconciled in Aristotle, and a consideration of artificial 

 fertiHsation would have provided a test case, had he been able to 

 know of the experiments of Delage and Loeb. For, on his second 

 theory, butyric acid would transmute a sea-urchin's egg into butyric 

 acid and not into a sea-urchin: while, on his first theory, the egg 

 would make the sea-urchin irrespective of what influence it was that 

 swung the starting-handle. 



Aristotle has a good deal to say about the theory of recapitulation, 

 as it was afterwards to be called. He thought there was no doubt 

 that the vegetative or nutritive soul existed in the unfertilised material 

 of the embryo, "for nobody", as he says, "would put down the un- 

 fertilised embryo as soulless or in every sense bereft of life (since 

 both the semen and the embryo of an animal have every bit as 

 much life as a plant) and it is productive up to a certain point. ... As 

 it develops it also acquires the sensitive soul in virtue of which an 

 animal is an animal. . . . For first of all such embryos seem to live 

 the life of a plant, and it is clear that we must be guided by this in 

 speaking of the sensitive and the rational soul. For all three kinds 

 of soul, not only the nutritive, must be possessed potentially before 



