SECTION V. : THE ANIMAL AS A WHOLE 



CHAPTER XXX 

 THE PRESERVATION OF NEUTRALITY 



" To test a principle by its consequences is allowed by good logic and enjoined 

 by sound reason." JOUBERT. 



FROM a physico-chemical standpoint, the animal body may be 

 considered as a polyphase liquid, the various phases being separated 

 from one another by a series of membranes of varying and variable 

 permeability. From the moment of origin of the organism as an 

 entity, that is, from the time when the conjugation of spermato- 

 zoon and ovum produced a mass of protoplasm which was not 

 in equilibrium with its environment, the various external forces 

 brought to bear on the organism still further accentuate this 

 disturbance. The sum of the changes termed life may be looked 

 on as the response of this polyphase-multimembrane-enclosed 

 liquid to these impacts. Briefly, all changes tend to restore 

 balance which, when attained, is death. It is difficult to make 

 statements on this subject without using terms implying purpose, 

 for example we speak of water reaching its own level cell adjust- 

 ing itself to its environment, etc. To use other terminology 

 would be cumbrous if correct. 



We dealt (Chap. XVI.) with the effect produced, on the internal 

 and external structure of bone, of altering the incidence of a load. 

 Not only are the nearby bones altered but even distant and 

 apparently unaffected bones undergo changes. In our study of 

 the transport system we saw how an alteration produced in one 

 part of an organism spread throughout the whole animal. 



One of the main functions of blood is to maintain constant the 

 concentration of hydrogen ions throughout the organism. A 

 slight potential increase in the acidity or alkalinity of the system 



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