i9ii] Jacoh Rosenhloom 275 



C. Watery condition of the blood (hydremia). 

 //. Factors causing diminished absorption. 



A. By lymphatics. 



(a) Paralysis of limbs. 



{b) Obstruction of lymphatic trunks. 



B. By veins. 



{a) Venous obstruction. 

 (&) Watery condition of the blood. 

 (c) Concentrated transudations. 

 Fischer's collochemical theory of edema is discussed in section 

 III of this Symposium (p. 279). 



II. THE EARLIER THEORIES OF EDEMA 

 Jacob Rosenbloom 



In a brief discussion of this subject, which is very comprehen- 

 sive, it is desirable to commence with the theory of Richard Bright 

 who, in 1827, published his views on edema. He believed that 

 edema was due to blood poor in albumin. The " thinned " blood 

 in his view reached the tissues by filtration while the normal blood 

 was too thick to pass through the vessel walls. It is interesting 

 to note that this theory held sway for about 50 years. Bartels pro- 

 posed a modification of Bright's theory by suggesting that the loss of 

 albumin was not the cause of edema but only a favorable factor for 

 an easy transudation of fluid constituents of the blood. In Bartel's 

 view edema was due to a retention of water in the blood leading to 

 a thinned condition of the serum and a correspondingly increased 

 amount of water in other fluids of the body, filtration playing the 

 principal part in the transudation process. Ludwig's work (1850) 

 on the secretion of saliva showed that the driving force of secre- 

 tion was inside the cell and not outside. Heidenhain's work 

 (1891) on absorption and on flow of lymph showed that neither 

 could be explained upon the basis of filtration and difTusion alone. 



In Order to test the theory of Bright and Bartels, Cohnheim 

 and Lichtheim (1877) injected intravenously 6 per cent. Solutions 

 of sodium chlorid into dogs and found that although an amount 

 of Salt equivalent to over 60 per cent. of the weight of the dog 



