PHYSIOLOGY OF CORTICAL INSUFFICIENCY 167 



tory disturbances in adrenal insufficiency. The abnormal com- 

 position of the blood will affect the nutrition and rhythmicity 

 of the heart and thus lead to its inefficiency, while the decrease 

 in the blood volume will vitiate the hemodynamic relationships 

 which make possible normal circulatory activity. The latter 

 factor is undoubtedly of greatest importance and is probably 

 responsible for the ultimate drop in blood pressure. 



THE BLOOD 



Changes in the blood are an important and frequent observa- 

 tion in animals in adrenal insufficiency. There is a loss of 

 fluid from the blood stream which results in a concentration of 

 the formed elements so that the relative volume of the red 

 blood corpuscles as determined by the hematocrite may rise 

 considerably. That this represents an actual loss of fluid from 

 the blood stream and not merely its transferral from plasma 

 to corpuscles is shown by the concomitant increase in the 

 number of red blood corpuscles, which is approximately propor- 

 tional to the observed increase in their volume as determined 

 by the hematocrite and by the increase in the total solids of 

 the plasma (Figure 10). 



The differential leucocyte count in adrenal insufficiency is 

 also altered from the normal. 126 Thus in cats, Zwemer and 

 Lyons 703 found a decrease in the relative number of polymor- 

 phonuclear neutrophiles with a corresponding increase in the 

 number of small mononuclear lymphocytes, similar to that ob- 

 served clinically in chronic wasting diseases. The above de- 

 scribed blood picture many be obscured by shock or infection. 



Several investigators have attempted to measure the de- 

 crease in blood volume during adrenal insufficiency. Unfor- 

 tunately the dye methods utilized for this purpose give entirely 

 unreliable results, as might be anticipated from a simple con- 

 sideration of the basis for the application of these methods. In 

 normal animals one allows a given length of time (empirically 

 determined) to elapse before drawing the blood sample in 



