166 FRANKLIN C. McLEAN 



lymph vessels dilated at autopsy in cases of generalized edema. Volhard 

 found, however, that in most cases this was not true, and he noted a 

 marked overflowing of the abdominal lymphatics in only two cases, in 

 both of which death occurred suddenly during diuresis. He concluded 

 that the lymph vessels have a great deal to do with the disappearance of 

 edema, especially during diuresis, but that they play little part during 

 the time that edema persists. 



Cell Metabolism and Edema. Various authors, Landerer, Lazarus- 

 Barlow, Loeb, Ziegler, Fischer, and Quincke have attributed edema to dis- 

 turbances of the mechanism by which the tissue cells withdraw fluid from 

 the blood and withhold it from the circulation. Although their conceptions 

 of the disturbance differ their conclusions rest upon the assumption of a 

 disturbance in cell metabolism. 



Cell Respiration and Edema. Following the work of Araki(c), in 

 which he showed that diminished oxygen supply to the tissues resulted in 

 incomplete oxidation of the products of metabolism, and the consequent 

 formation of lactic acid, Loeb(c) showed that interfering with the oxygen 

 supply might result in the swelling of the tissues and attributed this to an 

 increase in osmotic pressure, the result of acid formation. 



On the basis of experiments on the muscles of the frog's leg, similar 

 to those performed by Loeb, Fischer also came to the conclusion that edema 

 is due to increased acid formation. He attributed the edema to swelling 

 of the colloids, since increased acidity is known to increase the affinity 

 of colloids for water. Although there is some evidence of disturbances of 

 cell respiration in conditions associated with edema, particularly on 

 account of the formation of lactic acid in passive congestion, such acid 

 formation has not been shown to increase either the osmotic pressure of 

 the tissues, as Loeb thought, or the affinity of the colloids for water, 

 according to Fischer. 



Protein Metabolism and Edema. Edema caused by protein poison- 

 ing, as the result of ingestion or administration of foreign proteins, is a 

 part of an anaphylactic reaction. The pathological physiology of edema 

 of this form, usually manifested as urticaria or angioneurotic edema, is 

 not understood. 



Edema due to protein deficiency has been most striking in the cases of 

 war-edema or famine-edema which have been found frequently in the last 

 few years in the middle European countries (see Schnittenhelm and 

 Schlecht). It occurs apparently as a result of long-continued dietary de- 

 ficiency (Maver), and is probably due to lack of sufficient protein in the 

 diet (Kohman). There is no evidence of renal excretory insufficiency, 

 and patients usually recover rapidly when put to rest in bed and given a 

 salt poor diet. 



Inorganic Metabolism and Edema. The occurrence, persistence, or 

 disappearance of edema may depend either on the fluid or salt intake, or 



