191 1] William J. Gies 279 



24 hours, 15 per cent. ; after 7 days, 25-40 per cent. Similar results 

 were obtained in many experiments. In order that there might be 

 no possibility o£ an increase in blood pressure in spite of the liga- 

 ture, the muscles were cut from the frog and placed in salt Solution. 

 By this means there was no question of blood pressure and a lack 

 of oxygen was also produced. These muscles behaved like the liga- 

 tured muscles, showing conclusively that blood pressure had nothing 

 to do vvith the edema produced. Loeb made many other experiments 

 and came to the conclusion that edema iscaiised by chemical changes 

 which occur in the tissiies and which are mostly due to a lack of 

 oxygen. These changes lead to an increase in osmotic pressure, 

 which is greater in the tissues than in the blood and lymph, and 

 therefore the tissues take up fluid and become edematous. This 

 explanation seems very plausible and also accounts for the sodium 

 Chloride retention of the French school and the various kinds of 

 local edema. 



(Fischer's extension of Loeb's theory of edema is the subject of 

 the discussion to follow.) 



This brief sketch of the development of our ideas concerning 

 the cause of edema, emphasizes the fact that the farther we progress 

 in our knowledge of physiologic and pathologic phenomena, the more 

 we find that the ultimate causes reside in the tissues themselves. 

 Since tissue morphology and function are nothing but questions of 

 the nature and powers of the cells that compose a tissue, it is 

 obvious that there is great need for a thorough knowledge of the 

 chemical statics and dynamics of individual cells. It is in this field 

 that great advances must be made for the elucidation of many 

 physiological and pathological problems. 



III. FISCHER'S THEORY OF EDEMA 

 William J. Gies 



The most important recent contribution to our knowledge of 

 edema has been made by Fischer in an elaborate extension of the 

 werk and views that were published by Loeb several years ago 

 (p. 278). 



