EDEMA 



171 



TABLE IX 



TOTAL BLOOD AND PLASMA VOLUME AS RELATED TO BODY WEIGHT 



(Bock) 



ances in the tissues have been impressed by the increased molecular 

 concentration of the blood and the polycythemia in chronic heart failure, 

 and by the apparent dilution of the blood during the period of diuresis 

 accompanying the disappearance of edema, and have been ready to assume 

 that the volume of the blood might be diminished during the persistence 

 of edema. Krehl(<i) has considered the possibility of an increase in the 

 volume of the blood as a part of generalized edema, that is to say, an 

 "edema of the blood," and states that there is no reason why an increase 

 in the volume of the blood should not take place. On account of divergence 

 of opinion as to the part played by the total blood and plasma volume in 

 the occurrence of the edema, it is of importance to consider the evidence 

 as to their actual state. 



Bock(&) has recently studied the plasma volume and the total blood 

 volume in various conditions, using the vital red method of Keith, Rown- 

 tree, and Geraghty. He finds significant variations in the total blood 

 volume in certain pathological conditions associated with edema, but finds 

 that the ratio of the volume of blood plasma to body weight is practically 

 unchanged (Table IX). He also finds that in edema the relation of the 

 volume of blood plasma to the body weight remains undisturbed during 

 changes of the water content of the body. 



It will be seen, from Bock's data, that in none of his cases is there 

 an increase in the relation of the total blood volume to the body weight. 

 In the case of chronic nephritis with anemia there is a diminution in the 

 ratio of the total blood volume to the body weight, corresponding to the 

 diminution in volume of red blood cells, since in this case, as in the others, 

 the ratio of the plasma volume to body weight remains unchanged. Bock 

 has been particularly impressed with this relative constancy, and regards 

 it as the important result of his work. Attention should be called, how- 

 ever, to the decrease in actual volume of plasma, during the same period 



