METABOLISM AND THE DISTRIBUTION OF MATERIAL 221 



The serum of the cat had a higher water content than that of the 

 other animals experimented upon; the corpuscles also had a high 

 water content, even though not the highest; the entire blood, how- 

 ever, is only a little above the average. For Horse I, serum and 

 entire blood have minimum values and the corpuscles a low but 

 by no means the lowest value. In the case of Sheep I, the entire 

 blood reaches a maximum, whereas the blood corpuscles show a 

 minimum, and the serum possesses a water content a little above 

 the average. With the rabbit, there is a high water content in all 

 portions. From this we learn that a substance possessing a great 

 range of swelling exists in the whole blood, namely, the fibrinogen. 

 We recognize further, that the elements of the blood possess a cer- 

 tain elasticity, which smoothes out the fluctuations in the water 

 content, and which shows itself by a " lag " of the water plenitude 

 or poverty in the various elements of the blood, depending on 

 whether there is a supply or a withdrawal of water, a swelling or a 

 shrinking. 



The following swelling ranges are found for the various elements 

 of the blood: fibrin > whole blood > corpuscles > serum. It would 

 be desirable to have investigations of the water content of the differ- 

 ent elements of the blood in the same animal before and after water 

 has been given. 



What is it then, that determines the water content or swelling of an 

 organ? Undoubtedly each organ colloid has a definite swelling ca- 

 pacity and a definite swelling range. A priori, we may assume that 

 the colloids of muscles swell more than those of the epidermis. 

 Without doubt, the structure of the given colloid is also a factor. 

 W. PrEFFER* 2 (loc. cit. I, p. 61) justly emphasizes the distinction 

 between water of swelling, consequent upon the hydrophile state of 

 the swelling substances and the water of imbibition, which is drawn 

 up into the capillary interstices as into a sponge. 1 



E. PRIBRAM*! believes that the swelling of protoplasm in its true 

 sense, i.e , of the assimilated (species-native) colloids of the cell is con- 



1 W. PFEFFER speaks, it is true, of "molecular" water of imbibition (or ad- 

 herent water) and of "capillary" water of imbibition, yet he intends the same 

 distinction that I have indicated above. 



