200 MAN, THE ANIMAL 



began to be an exact science. He was the first 

 to show that a chemical equation was really an 

 algebraic equation also and when three factors 

 were given, the missing one could be computed. 

 This implied definite causal relations and from 

 this time on to the present, the scientific method 

 has superseded all others. 



Biology began to feel the influence of the rela- 

 tionship idea much earlier than chemistry. Sev- 

 eral workers had been trying to show that animals 

 and plants could be arranged into groups before 

 Linnaeus in 1758 devised a scheme of classifica- 

 tion based on relationships that has been retained 

 until the present. Numerous workers on embry- 

 ology laid special emphasis on the long series of 

 changes between the ovum and the chick before 

 the time of Darwin. Here one finds the names of 

 such famous men as Harvey, Malphighi, Wolf 

 and Von Baer. But it was finally reserved for 

 Darwin to apply the method of cause and effect 

 In such a manner as to revolutionize the manner 

 of thinking not only of biologists but of those in 

 other realms of knowledge as well. Let him tell 

 how he did it. "By collecting all facts which bore 

 In any way on the variation of animals and plants 

 under domestication and nature, some light might 

 perhaps be thrown on the whole subject. My 

 first note-book was opened In July, 1837. I 

 worked on true Baconian principles, and, without 



