I9I2] Martin H. Fischer 447 



causation of edema is concerned, it is not necessary that the acid be 

 " free" ; in fact, so far as we know now, it is the "combined" acid 

 that leads to the increased hydration. To satisfy the laws of equi- 

 librium only a theoretical amount of " free " acid need be present. 



Does a fluid of this kind have the power of exciting edema in a 

 normal tissue ; or of causing such colloids as fibrin, when immersed in 

 it, to swell ; or of absorbing more water than that attracted by an equal 

 volume of similar juice from normal tissue of the same kind? 

 (Page 305.) 



Heinicke, I think, first showed that the injection of blood serum 

 from a rabbit, rendered nephritic and edematous by injection of 

 uranium nitrate, into a second rabbit made this edematous. But I 

 do not feel that too much weight should be laid upon this finding. 



All the water in normal or abnormal blood and lymph is held 

 as hydration water, in combination with the protein colloids. 

 Whether fibrin or any other colloid can take water away from them 

 depends upon whether it has a greater affinity for the water than 

 the colloids of the blood or lymph. 



Does the minimal Proportion of lactic acid which is capable of 

 inducing edema in a living tissue destroy the life of any of the cells 

 or definitely impair normal cellular activity ? ( Page 306. ) 



It does not destroy life. Whether it impairs normal "cellular 

 activity" is a matter of definition. A rabbit can be made to hold 

 in water an extra ten or twenty per cent. of its body weight after 

 having been injected with acid, and yet the uninitiated laboratory 

 worker may be unable to recognize any change at all in the animal. 



Does such a proportion of lactic acid remove from its setting in 

 protoplasm any basic factor of importance in the essential intracellular 

 coördinations ? ( Page 306. ) 



If I understand this remark correctly, I would say that it de- 

 pends upon the criterion chosen. A little swelling of the liver does 

 not seem to be serious. The same degree of swelling blinds an eye. 



In Fischer's view the water of edema diffuses from the capil- 

 laries to the tissue spaces and thence into the cells in response to the 

 attraction exerted for it there by intracellular colloids under the 



