294 Fischer's Theory of Edema [Dec. 



insomemore or less fixed way with the rest of the corpuscle. The lack 

 of evidence to show that this combination between stroma and hemo- 

 globin is a chemical one, and the f act that an enormous amount of hemo- 

 globin is held by a very small amount of stroma leads me to assume 

 that the combination between the hemoglobin and the rest of the cor- 

 puscle represents an adsorption phenomenon (p. 170). The retention 

 and loss of color by carmine-stained fibrin is very similar to, and occurs 

 under the same conditions as, the retention and loss of hemoglobin by 

 the red blood corpuscles (p. 171). The relationships between the dif- 

 ferent colloids in the case of the red blood corpuscles are, of course, 

 much more complicated than in the case of carmine-colored fibrin. In 

 place of only two colloids, we have in the red blood corpuscles at least 

 four to deal with, and this makes for an infinitely more complicated 

 System (p. 173). 



The question to which anyone discussing the general problem of 

 growth (increase of volume) is most desirous of getting an answer is 

 this: What is the source of the energy for growth? . . . The pressures 

 exerted by swelling colloids constitute an adequate source. . . . An 

 absolute sine qua non for growth is the presence of water. . . . All 

 growth in volume is preceded by the production of various (hydrophilic 

 or emulsion) colloids. But not only are various colloids produced, but 

 conditions which particularly favor the absorption of water by these 

 colloids are also instituted. It is the rule, for example, that the grow- 

 ing tips of plants have an acid reaction; and the role of acids in making 

 various emulsion colloids swell is familiär to us f rom previous consider- 

 ations (p. 175). The colloidal conception of water absorption also gives 

 US the means of understanding the mechanism of certain growth curva- 

 tures, and curvatures due to tropisms of various kinds as manifested 

 in plants and animals (p. 176). The effect of an increased growth, as 

 evidenced particularly through the presence of an increased amount of 

 water in the convex portion of the plant stem or root, or the animal 

 organism, over that of the convex portion, best explains the observed 

 phenomenon (p. 177) . In conclusion, let attention be called to the ready 

 explanation which the colloidal conception of water absorption offers 

 of the ways and means by which it has been found that certain plants 

 and animals protect themselves f rom a loss of water. , . . When water 

 is scarce certain plants convert some of their starch into oxalic acid. 

 Those types of plants which under natural conditions are most liable 

 to suffer from lack of water (the succulents) seem all to possess the 

 interesting property of reducing their output of carbon dioxide, while 



