CHAPTER XX 



Mammalia — Physiology 



Man is an animal. We see this more and more as we study the 

 structure and vital phenomena of other animal organisms. Co7n- 

 parative Anatomy shows the structure to be comparable and animals 

 have been grouped in a series ranging from the simple one-celled 

 animal to man in all his complexity. Embryology shows us that man 

 conforms to the Law of Development just as inflexibly as does the 

 simplest invertebrate. Comparative Embryology shows a striking 

 similarity between the embryo of man in its early stages and the 

 embryos of other mammals at corresponding periods in their devel- 

 opment. But it is in the study of the vital phenomena, Physiology, 

 that we find the greatest similarity. There is a wide variation in the 

 degree of specialization of organs for certain functions, but there is 

 in all living animals a property that separates them from the non- 

 living by a seemingly unbridgeable chasm. 



The late Jacques Loeb, of the Rockefeller Institute, artificially 

 fertilized the eggs of the sea urchin and the starfish by chemicals, 

 and to his great disgust, the reporters announced that he had pro- 

 duced life. Jarring, varying temperatures, and differences in the 

 salinity of the water produce the same effect in Nature. All 

 sciences have theories regarding the origin of life, but no theory is 

 without a flaw. Granting that chemicals can be combined to pro- 

 duce life, we have proved nothing. We have pushed back the ques- 

 tion a little farther. We have not shown the nature of the phenom- 

 enon which causes the chemicals to combine. This is life perhaps. 

 Electricity may be life in one sense. However, we cannot prove the 

 spontaneous generation of life. We are able to vary conditions in 

 the case of developing eggs and get different results but we cannot 

 introduce the spark of life. Lovatt Evans said (1928) in his address 

 before the British Association for the Advancement of Science: 

 " Science can not fathom the mystery of life." 



Man vs. the Higher Apes 



In man and the higher apes the similarity of structure is carried 

 out even to the finer details of the brain. The brain weight and 



420 



