44 THE NEW PHYSIOLOGY. 



use to suggest to a physiologist that when an Arcella is 

 in difficulties owing to deficiency of oxygen in the water, 

 or a fish is lying helpless on the bottom because it has 

 lost the gas in its swim-bladder, or a mountain climber 

 is in difficulty from deficient oxygen-pressure in the air, 

 the " entelechy " decrees that in order to put things 

 right the ordinary chemical processes in animal proto- 

 plasm shall be reversed, and that oxygen shall be liberated 

 from combination instead of entering into or remaining in 

 it. The physiologist will instinctively look for the actual 

 stimulus and its biological interpretation. This is the 

 only right and rational course, justified abundantly by 

 experience. We neither need, nor will have, any ghosts 

 in physiology ! The mechanists are right in rejecting 

 vitalism, and the vitalists are also right in rejecting the 

 mechanistic theory ; but there is no reason for accepting 

 either theory. What biology requires to do is to go back 

 to ordinary observation, and to realise that the ordinary 

 work-a-day conception of a living organism — the con- 

 ception which I have already endeavoured to explain 

 and illustrate to you — is the only working hypothesis 

 which will actually work, and is just as necessary in 

 biology as the fundamental conceptions of mathematics, 

 or physics, or chemistry, are in these sciences. 



If we are to get a grip of biological fact — the grip 

 which enables us to predict — we must always keep the 

 whole life of the organism in view, whether that organism 

 be a single cell, or a compound organism, or a species. 

 Thus to investigate respiration without keeping in view 

 the circulation, the action of the kidneys, nervous 

 system and other organs, and all that is roughly included 

 in the term " general metabolism," is work which will 



