I] CHEMICAL EMBRYOLOGY 13 



Gotch has given a delightful account of the evening of AristoteUanism, 

 but it involved a stormy sunset, and the older ideas did not give 

 way without a struggle. Harvey's work is perfectly representative of 

 the period of transition, for, in his preface under the heading "Of the 

 Method to be observed in the knowledge of Generation", he says, 

 "Every inquisition is to be derived from its Causes, and chiefly from 

 the Material and Efficient". As for the formal cause. Bacon expressly 

 excluded it from Physic, and it quietly disappeared as men saw that 

 scientific laws depended on the repeatableness of phenomena, and 

 that anything unique or individual stood outside the scope of science. 

 Thus in the case of the developing egg, the formal (the particular 

 farmyard, etc.) and the final causes are scientifically meaningless, 

 and if it were desired to express modern scientific explanation in 

 Aristotelian terminology, the material and efficient causes would 

 alone be spoken of, essence-of-eggness being a "chymical matter" 

 as well as the heat of the brooding hen. 



Obstacles to Chemical Embryology 



The complexity of living systems, however, is such that many 

 minds find it difficult to accept this physico-chemical account as the 

 most truly scientific way of looking at it. This is doubtless due in part 

 to an erroneous notion, which is yet very tenacious of existence, that 

 the mechanical theory of the universe must, if accepted at all, be 

 accepted as an ultimate ontological doctrine, and so involve its sup- 

 porter in one of the classical varieties of metaphysical materialism. 

 It cannot be too strongly asserted that this is not the case. To imagine 

 that it is, is to take no account of the great space that separates us 

 from the last century. "When the first mathematical, logical, and 

 natural uniformities", said WilHam James, "the first Laws, were 

 discovered, men were so carried away by the clearness, beauty, and 

 simplification that resulted that they believed themselves to have 

 deciphered authentically the eternal thoughts of the Almighty. His 

 mind also thundered and reverberated in syllogisms. He also thought 

 in conic sections, squares, and roots and ratios, and geometrised like 

 Euclid. He made Kepler's laws for the planets to follow, he made 

 velocity increase proportionately to the time in falhng bodies; he 

 made the laws of the sines for light to obey when refracted; he 

 established the classes, orders, families, and genera of plants and 

 animals, and fixed the distances between them." 



