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latter part of this statement. To my mind it sums up all that is 
vicious in the modern mechanistic attitude of physiologists and 
biologists. We are certainly not justified in assuming anything of 
the kind. We may say that, possibly, when v T e have more 
perfect knowledge, all can be explained by ordinary physico-chemical 
laws; but just so can the vitalists say that more perfect knowledge 
will indicate the impossibility of physico-chemical explanation. 
Driesch, after a long and successful study by experiment, has 
formulated a theory of some importance in any discussion on vital- 
ism. He expounded his theory in the Gifford lectures given at Aber- 
deen in the year 1907. 1 Yet not once in Schafer’s address are those 
experiments or the conclusions of Driesch referred to. We are sim- 
ply led to assume that from the success in explaining some vital 
processes by physics and chemistry we must take for granted that all 
vital phenomena will be some day similarly explained. This is not a 
scientific attitude. 
One might well use Johnstone’s words 2 in reply to the physiolo- 
gists — -“Did physiology, that is the physiology of the schools, ever 
really investigate the organism? A muscle nerve preparation, 
an excised kidney through which blood is perfused these things 
are not organisms.” It seems very probable indeed that many of the 
changes taking place in the living body are purely chemical changes, 
and that many organs are operated by physico-chemical processes. 
We must, however, guard ourselves from confusing the cause and 
controlling factor or factors with the means by which they act. 
The phenomena of the living organism which call for explana- 
tion may be classified as follows : — 
Group (a.) The phenomena dealing with the growth of the or- 
ganism in the widest sense of the word — that is 
to say inclusive both of development from the egg, 
and the regeneration of lost parts. 
Group (b.) The phenomena dealing with the evolution of the 
species — transformism. 
Group (c.) The phenomena of the actual functioning of the 
organism — the modus operandi of its organs — the 
methods by which energy is obtained for growth 
and upkeep. 
The believers in the all-sufficiency of physico-chemical explanations 
have achieved their greatest successes in the study by experiment of 
the phenomena coming under Group (c.). 
Their conception of life phenomena would compel 11 s to regard 
the successive stages in the growth of the organism (Group (a.) 
above) as phases in a complex physico-chemical system. The same 
thing would apply to their explanation of the steps in the evolution 
of the species. 
Driesch, Science and Philosophy of the Organism London, 1 908. 
- Johnstone. The Philosophy of Biology. Cambridge, 1914. 
