116 THE FITNESS OF THE ENVIRONMENT 



stance (in the case of the cow) is roughly as 

 follows : ' — 



Parts per 1000 



Water 913.6 



Protein 72.5 



Sugar 1.05 



Cholesterine 1.24 



Lecithine 1.68 



Fat 0.93 



Organic phosphoric acid 0.01 



Na 2 4.31 



K 2 0.26 



CaO 0.12 



MgO 0.45 



CI 3.69 



P 2 5 0.08 



Most of these substances are in solution, 

 and unquestionably a host of others are pres- 

 ent with them, in small and varying amounts. 

 Among these may be mentioned iodine, 

 bromine, iron, sulphates, urea, ammonia, ben- 

 zoic acid, amino-acids, etc. But indeed all 

 substances found in urine (see below) also 

 occur in blood. It cannot be doubted that 

 if the vehicle of the blood were other than 

 water, the dissolved substances would be 

 greatly restricted in variety and in quantity, 

 nor that such restriction must needs be ac- 

 companied by a corresponding restriction of 

 the life processes. 



1 A full discussion of the following data may be found in 

 such works as those of Hammarsten and Abderhalden on 

 physiological chemistry. 



