ORGANIC REGULATION 105 
such instances, their presence and formation is organic- 
ally determined by something beyond; and of this 
something we can form no physical or chemical pic- 
ture. We also realise more clearly that in following 
the physical and chemical picture of the oxygen from 
the outset we have only done so by ignoring the organic 
control which, though present, seems less intimate. 
We have ignored, or put aside for the time, the regu- 
lated maintenance of breathing, the maintenance of 
the delicate normal structure of the lungs and of other 
parts connected with breathing, the regulation of the 
circulation and of the composition of the blood, and 
the maintenance of endless other things in which 
organic regulation manifests itself. But when we 
reach the living tissues we can ignore the organic regu- 
lation no longer: for we can see nothing clearly except 
an evident manifestation of the most intimate organic 
regulation. The physical and chemical picture is 
entirely obliterated by the picture of organism. 
We may reflect that although we cannot at present 
trace the combinations into which oxygen enters in the 
living tissues, yet the oxygen atoms are there in some 
form. We can demonstrate their presence by ele- 
mentary analysis, and we can separate chemical com- 
pounds, such as proteins, which contain oxygen. It 
can therefore be only a matter of further investigation 
to discover how the oxygen and other atoms combine 
in the living tissues and how these compounds react 
with one another to bring about the phenomena of life. 
This reflection brings us very close to a fundamental 
question. Physics and chemistry have brought us not 
