124 FRANK A. HARTMAJST 



(see reaction of the suprarenal to various conditions) has been inter- 

 preted by some as due to hyperactivity rather than .to a mere intoxication. 

 Of course the toxic lesions might develop if the gland were unable to cope 

 with the situation. However, these interpretations seem somewhat specu- 

 lative in the present state of our knowledge. 



The observations of Elliott and Tuckett seem to establish a relation 

 between the skeletal musculature and the cortex. In the first place the 

 lower a species is in the vertebrate scale the smaller is the proportion of 

 cortical to chromaphil tissue at least in mammals. During the course of 

 development of the individual, the cortex increases considerably while the 

 medulla changes but slightly. In the guinea pig an increase in the weight, 

 of the body to five times is accompanied by a cortical increase of twelve 

 times with little change in the medulla. 



It is pointed out in connection with epinephrin effects on muscle, 

 that the cortex becomes vacuolated after prolonged excessive muscular ex- 

 ertion. This may indicate hyperactivity due either to increased detoxi- 

 cation of the products of fatigue or to augmented secretory processes. 

 If it could be shown that epinephrin precursors originate in the cortex, 

 knowing the value of epinephrin in preventing the onset of fatigue,, there 

 would be cause to assume that such cortical vacuolation is the result of 

 hypersecretion. There is some evidence of secretory activity on the part 

 of the cortex. The doubly refracting substance increases during rest 

 but decreases following muscular activity (Elliott and Tuckett). 



All observations point to the importance of the suprarenal cortex., 

 Throughout the vertebrate kingdom the cortex is the more constant of the 

 two parts of the gland. It develops rapidly during the early growth of 

 the individual and persists through old age. During conditions of stress 

 it hypertrophies. Thus it enlarges during pregnancy and lactation, and 

 perhaps also accompanying increased muscular development. It responds 

 to toxins and infections in a manner not yet understood. These changes 

 certainly indicate a valuable function. 



Relation of Suprarenals to Growth 



The suprarenals appear to bear a direct relationship to growth and 

 reproduction, which is but a phase of growth. 



In the first place it has been shown by R. G. and A. D. Hoskins that 

 the suprarenal stimulates the growth of the gonads. They fed desiccated 

 suprarenal to a series of forty-eight rats beginning at about the age of 

 twenty days and lasting over a period of from two to eight weeks. These 

 animals were fed daily as much dried suprarenal as could safely be given 

 without causing digestive disturbances. It was found that no difference 

 developed in the weight of the other ductless glands when compared to 



