XXI 



THE PHYSIOLOGICAL PROBLEMS OF TODAY 1 



IF it be true that the fundamental problem of physics is 

 the constitution of matter, it is equally true that the funda- 

 mental problem of physiology is the constitution of living 

 matter. I think the time has come for physiology to return 

 to its fundamental problem. 



"Living matter" is a collective term for the qualities 

 common to all living organisms. Comparative physiology 

 alone enables us to discriminate between the general proper- 

 ties of living matter and the functions of specific organs, such 

 as the blood, the nerves, the sense organs, chlorophyll, etc. 

 Nothing has retarded the progress of physiology and pathol- 

 ogy more than the neglect of comparative physiology. Com- 

 parative physiology shows that secretion is a general function 

 of all living organisms and occurs even where there is no 

 circulation. Hence it was a priori false and a waste of time 

 to attempt to explain secretion from experiments on blood- 

 pressure. Oxidations occur regardless of circulation, and it 

 was a priori a waste of time to consider the blood as the seat 

 of oxidation. Comparative physiology has shown that the 

 reactions of animals to light are identical with the heliotropic 

 phenomena in plants. Hence it is a mistake to ascribe such 

 reactions as the flying of the moth into the flame to specific 

 functions of the brain and the eyes. Sleep is a phenomenon 

 which occurs in insects and plants, and it would be a waste 

 of time to attempt an explanation of sleep on the basis of 

 phenomena of circulation. The best interests of physiology 



1 Address delivered at the meeting of the American Society of Naturalists, Ithaca, 

 1897. This paper was one of seven upon " The Biological Problems of Today," each 

 speaker being limited to ten minutes. 



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