iQii] William J. Gies 295 



producing at the same time various organic acids as soon as subjected 

 to unfavorable conditions for growth. These phenomena of acid pro- 

 duction have been generally interpreted as meaning that by such methods 

 the plant increases the number of soluble molecules in its cell Contents 

 and so increases its osmotic pressure. A more correct explanation, it 

 seems to me, is this — through the production of these acids the affinity 

 of the plant colloids for water is increased, so that the agencies oper- 

 ating to rob it of this water are counteracted. A question that awaits 

 an answer in the case of animals is whether a like production of acids 

 is responsible here also for the maintenance of a normal water content, 

 as when a fish, for example, born in fresh water, moves out to sea 

 (p. 179). 



On the secretion of urine. The secretion of urine is con- 

 sidered from the viewpoint of the facts of colloidal hydrophilia 

 (p. 180-204), Fischer comments in part as follows on the more 

 important phases of this subject: 



It follows as a necessary conclusion from the argument which has 

 been the bürden of this paper, that in the resting State the living organ- 

 ism represents a series of different (hydrophilic) emulsion colloids 

 saturated with water. That they are saturated is evidenced by the fact 

 that we cannot make the organism as a whole absorb any more water 

 or give up any without antecedent chemical changes. In consequence, 

 an organism not subject to any marked changes from without or 

 within maintains a constant weight over long periods of time. We need 

 but recall how all the secretions of a man undergoing absolute starva- 

 tion drop to practically nothing, and how, on the other band, the con- 

 sumption of even enormous amounts of water by the normal individual 

 does not lead to the development of the slightest edema. We are accus- 

 tomed to say that the kidneys quickly rid the body of any excess of 

 water. Just why this is done is not so apparent, though we will sug- 

 gest an explanation right away. Let it first be pointed out that the 

 blood and lymph constitute an integral part of this water-saturated 

 colloidal System which makes up the body. It may at first sight seem 

 somewhat surprising that the relation between the colloids and the 

 water of liquid (hydrophilic) colloidal Solutions (sols) is identical with 

 that of the relation existing between water and solid colloids (gels) 

 such as fibrin. But such an identity is not only demanded by theory 

 but has been proved experimentally by the recent work of Wolf gang 

 Pauli and Hans Handovsky^*^ on the blood serum. (Page 184.) 



^* Pauli and Handovsky : Biochemische Zeitschrift, 1909, xviii, p. 340. 



