Discussion 61 



A large blood transfusion elicited a considerable water diuresis and the 

 blood sodium rose to normal, while the oedema fluid was excreted. 



With both the high and the low sodium concentrations the circulation 

 was inadequate. In the first instance the excess of sodium and a less 

 considerable excess of water was excreted as soon as the normal blood 

 volume was restored. In the second the rise in blood volume led to the 

 elimination of the excess of water and of a less considerable excess of salt. 



The interesting observations of Dr. Schwartz and Dr. Fourman show 

 that variations in circulation may not always be the primary factor in 

 the excretion of sodium and water. It is, however, difficult to distinguish 

 renal responses to variations in the circulation from other reactions on 

 the part of the kidneys. jNIoreover any considerable loss or retention of 

 salt and water has an effect on the circulation. The problem is that an 

 excess or an inadequacy of the circulation in patients cannot be measured 

 in a satisfactory way. Since this factor cannot be disregarded we have to 

 estimate it on the basis of indirect evidence. 



