ENERGY TRANSFORMATIONS IN LIVING MATTER 137 



It is not intended at all to represent that the phenomena 

 described are contrary to the laws of energetics, but to make 

 clear that the cell does not play the part of an inert membrane, 

 that the laws of osmosis deduced from observations on inert 

 membranes do not apply, and that there is a form of energy and 

 type of energy transformer at work which are not to be observed 

 elsewhere than in living cells. 



The study of the properties of this particular energy trans- 

 former, and the interactions between biotic energy and the inorganic 

 forms of energy carried out by its action, is the province of the 

 biologist, who must approach and has been approaching the subject 

 in the same manner as the physicist and chemist approach the study 

 of other types of energy that is, by acting upon the cell with other 

 types of energy, and studying its reaction to such treatment. 



Experiments on any form of energy consist in observing the 

 interactions between it and other forms, in studying the nature 

 of the transformer, and of the changes, if any, which occur in it. 



The structure of the cell must hence be taken up from the 

 point of view of its function; and we must study the chemical 

 and physical composition, the effect of the several constituents 

 upon one another, and upon the medium in which the cell lives, 

 the nature and action of the input and output of the cell, including 

 its secretions and how these are produced, the osmotic phenomena 

 and the effects of changes in the surrounding medium, the charac- 

 teristic accompaniments of stimulation of the cell and of conduction 

 of stimulation from part to part, and the effects produced by cells 

 possessing a life in common, as in the multicellular animal. 



Physical chemistry affords us one of the most powerful ex- 

 perimental engines in conducting such inquiries for a reason which 

 has already been touched upon namely, that the living cell is in 

 structure a complex solution containing both colloids and crystal- 

 loids, and that the chemical reactions occurring in the cell are 

 reactions in solution. Accordingly, although the whole matter 

 is profoundly affected by the fact that the cell is alive, it is evident 

 that our knowledge of cellular activities must be based on know- 

 ledge of the properties of solutions, both of colloids and crystalloids ; 

 of reactions in solution, the velocity of such reactions and the 

 conditions of equilibrium; of the mutual effect of crystalloids and 

 colloids upon one another when in common solution, and of the 

 effects of the living cell as a peculiar energy transformer upon 

 osmosis and diffusion. 



