VARIATIONS IN ADRENAL FUNCTIONAL ACTIVITY. 19 



doses of virulent cultures into two groups of guinea-pigs, the 

 animals constituting one of the groups having each been de- 

 prived of one suprarenal gland. The group of normal animals 

 lived altogether 138 hours; that of mutilated animals 150 

 hours. Several experiments of the same kind were performed; 

 invariably did they find that the animals from which one gland 

 had been extirpated lived longer than those left in their nor- 

 mal condition. The differential contractility of vessels and 

 capillaries referred to render this phenomenon a normal con- 

 sequence under the circumstances: The caliber of the muscular 

 vessels, veins, and arteries of the mutilated animals having be- 

 come enlarged and their walls relaxed by the loss of supra- 

 renal stimulus, engorgement of the larger trunks occurred, and 

 caused depletion of the remote capillaries, including those of the 

 bulbar and other neighboring centers. The toxics injected 

 producing their main primary effects upon the latter, and, the 

 quantity of toxic blood transported to them in a given time 

 being smaller than in a normal animal, the longevity of the 

 latter was prolonged in proportion. 



We will frequently refer in subsequent chapters to this 

 relative behavior of vessels under the effects of suprarenal 

 secretion or extract; the view, therefore, that vessels supplied 

 with a muscular coat and capillaries are antagonistic in con- 

 traction and dilation is only submitted as a postulate for the 

 time being. 



VARIATIONS IN THE FUNCTIONAL ACTIVITY OF THE 

 ADRENALS. 



ADKENAL INSUFFICIENCY AND ITS CAUSES. Analogy sug- 

 gests that, besides the normal standard of suprarenal activity, 

 there must be excessive and inadequate activity, both physio- 

 logical to a certain extent, but pathological when extremes are 

 approached. Haemorrhage into the adrenals under such con- 

 ditions would seem, at least, to represent one of the extremes, 

 but which extreme: overactivity or insufficiency? In other 

 words, acute intoxication is attended, we have seen, by an 

 overwhelming increase of blood in the organs, and death seems . 

 to follow through cessation of adrenal functions. Is this 

 arrest of action due to the haemorrhage, or is the haemorrhage 



