I.— PHYSIOLOGY. 163 



I have, I hope, said enough to lend emphasis to my principal point, 

 which is that the subject of physiology has the most intimate and vital 

 contact with all biological subjects, with the fundamental sciences, and 

 with medicine. It is, in fact, one of the best possible illustrations of 

 Herbert Spencer's idea that ' the sciences are arts to one another.' It 

 has often been said that science knows no frontiers and no nationalities. 

 If we apply this a little nearer home we shall all look forward to the day 

 when departments will merely indicate administrative boundaries and 

 not intellectual compartments. In the meantime it is to be hoped that 

 increasing numbers of young people specially trained in other sciences 

 will think it worth their while to try to understand what physiology is 

 and what it is striving for, and that they will come to our aid with their 

 own special implements and standpoints. 



Philosophical Position. 



Although the application of those sciences which are called ' exact ' 

 is of immense value to physiology, we must be under no misapprehension 

 as to their real relation, which is merely that they enable the phenomena 

 of life to be described more accurately. They in no way furnish an 

 explanation of those phenomena or enable us, without direct reference to 

 physiological facts, to forecast them. The so-called exact sciences appear 

 to be so because of the simplifications of which they are capable, by reason 

 of which problems can readily be formulated and attacked. Disturbing 

 conditions can provisionally be ignored or allowed for, and a first approxi- 

 mation reached which can be corrected later. In biology this can less 

 readily be done. It is the failure to appreciate this elementary fact which 

 leads some of those trained only in the methods of the exact sciences into 

 the most palpable and unpardonable blunders when they attack biological 

 problems. To take a simple illustration, no amount of pure physics, 

 chemistry and mathematics would have enabled the intricate and beautiful 

 physico-chemical adaptations which have been shown by L. J. Henderson 

 to happen in blood, to have been predicted, because these adaptations 

 depend, among other things, on the presence of membranes round the 

 red cells, fashioned by the living cells and having properties incapable of 

 prediction. The investigation of the equilibria themselves, in their 

 physiological significance, was a necessary preliminary to the introduction 

 of physico-chemical theory. When these phenomena, and deductions 

 from them, became known, it was possible for the physical chemist to 

 step in, apply the appropriate theories, and thus enable the phenomena 

 to be more accurately described in his own language. 



But the fact remains that this description turns entirely on the postu- 

 lated physico-chemical properties of the membranes as deduced from 

 their actual behaviour under given conditions in what are in reality 

 physiological experiments. It brings us no nearer to an explanation, 

 perhaps, but it certainly does enable us to link up some of the phenomena 

 of life with phenomena in the non-living, and so to describe them in 

 terms which we think we understand better, because for some reason 

 we regard physics and chemistry as more fundamental sciences than 

 biology. Whether they are really more exact, however, is a point which 

 might be debated. 



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