METABOLISM AND THE DISTRIBUTION OF MATERIAL 217 



shows that the condition and age of protoplasm when frozen, i.e., at 

 the lethal point, is similar to that observed by VAN BEMMELEN in the 

 drying of colloids; when the latter are frozen, they become optically 

 inhomogeneous, and their staining capacity changes. 



For normal functioning there is an indispensable normal water 

 content for every individual or- 

 ganism and organ. 



The total water content of an 

 organism gives us an idea of its 

 water requirements; the water 

 content of the individual organs 

 informs us about the distribution 

 of water in the organism. 



A clearer idea is obtained by 

 observing the distribution of 

 water in animals especially in 

 mammals. In Table III (see p. 

 219), I have compiled the water 

 content of the different adult organs 

 from available data. Table II 

 (p. 218) shows the distribution 

 of the total water content (100 

 per cent) in the various organs. 

 I have placed the proportionate 

 weights of the organs to the 

 total weight alongside for com- 

 parison. The data in Tables I 

 and II show far-reaching differ- 

 ences (see especially Skin in 

 Table II), for which age and nu- 

 tritive condition are responsible. 



In healthy animals and men, there is a definite swelling ratio for 

 the individual organs, a dynamic equilibrium. The maximal varia- 

 tion of normal swelling, more or less, is called the swelling range. 1 It 



1 Definitions: 



Swelling capacity is the maximal capacity for absorbing water, expressed in 

 W (weight of water) 



D (dry weight) 



Swelling is the water content of a gel or an organ expressed in 



W 



FIG. 37. Spirogyra: a, before the ex- 

 periment; b, frozen; c, after thawing. 

 (From H. Molisch.) 



Swelling range is the greatest variation in the capacity of an organ to absorb 

 water under different conditions. 



W (maximal weight of water) W (minimal weight of water) 



D 

 A normal swelling range and an abnormal swelling range exist. 



