ADAPTATION 185 



are these " processes 5: ' a priori regarded as being physical 

 or chemical themselves : indeed, we have learned that in one 

 large field, in the differentiation of our harmonious systems 

 they certainly are not. Now, if the metabolism does not 

 end in any change of visible form, then true physiological 

 processes, or more particularly physiological regulations, are 

 going on before us. But we are dealing with morphogenetic 

 events or regulations, if the result of metabolism is marked 

 by any change in the constituents of form. This however 

 may depend on rather secondary differences as to the nature 

 of regulation itself, and any kind of metabolism may really 

 be of the regulatory type, whether we actually see its result 

 as a constituent of form, e.g. owing to the production of 

 some insoluble compound, or whether we do not. 



I do not mean to say that these are the only differences 

 between mere physiological activities or regulations and 

 organogenesis proper, as an originating of typical form- 

 combination ; but if we regard, as we do in this chapter, 

 the given organisation of a living being as a substratum 

 of its functional life, morphological and physiological 

 adaptations are indeed of almost the same logical order. 



We had best therefore begin our discussions with a 

 recapitulation of our problem. We are studying adaptations 

 in functioning that means we want to know how the 

 organism behaves with regard to any change which may 

 take place in its functional state. We apply the term 

 regulation, or in particular adaptation, to any kind of 

 reaction on the part of the organism which re-establishes 

 the normal state of functioning, and we now want to learn 

 to what degree such adaptations exist in the field of 

 physiology. 



