INTEODUCTION 13 



Of course, most of the objectives were not apparent, or even 

 implicit, in the initial conscious formulations of this investigation. 

 As in all studies, possibilities became evident as the methods and 

 results accumulated. Initially the research appeared only as a 

 means of relating certain quantities from studies of water in organ- 

 isms. Thereafter the generality of the relations and their role in 

 regulations gradually unfolded. It is also fair to say that I have 

 long hoped to find general methods of understanding regulations 

 in organisms, and it is almost usual that methods turn up to the 

 conditioned (prepared) mind. 



The inquiry is divided into two chief parts : Part A deals with 

 selected data and aspects of ivater exchanges and water content. 

 Generalizations among measured quantities concerned with main- 

 tenance of water metabolism lead, in Paet B, to comparison and 

 extension of the same types of description to other components and 

 exchanges. In this way certain general methods of study and 

 some general properties of physiological processes are examined. 



