XXI 
THE PHYSIOLOGICAL PROBLEMS OF TODAY! 
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 prior? 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 priort 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. 
497 
Digitized by Microsoft® 
