PHYSIOLOGY AND EXPERIMENTAL PATHOLOGY 119 



generation of new tissue, regeneration gradually spreading through the 

 necrosed region. It took about five months for the stabilization of de- 

 generation and regeneration. 



Strictly speaking these experiments do not deal with true grafts. 

 Moreover no practical application could ever be made of such an operation. 

 The really valid examples of successful grafts were those obtained by 

 Busch, Leonard and Wright. A sagittal third of a suprarenal of the 

 same or of another animal was introduced into an opening in the lower 

 pole of the kidney cortex, patterned as nearly as possible after the graft. 

 The graft was held in place by sutures which brought together the cut 

 edges of the kidney. Blood-clot between the surfaces of the graft and the 

 kidney was prevented as far as possible. 



Grafts developed in three rabbits so that suprarenal insufficiency failed 

 to appear when the remaining suprarenal tissue was removed. Two were 

 autotransplants while one was a heterotransplant. That these grafts 

 functioned was shown by the symptoms of suprarenal insufficiency and 

 death following their removal. Medullary tissue was evident histologically 

 and chemically (reaction to chromate). 



There was evidence of medullary function in two other cases although 

 on account of the presence of accessory suprarenals, removal of the grafts 

 did not produce death in spite of the fact that the other suprarenal had 

 been removed. 



The guinea pig is very unusual in its behavior to grafts. Elliott and 

 Tuckett found that subcutaneous transplants from the bullock, sheep, 

 rabbit, rat, hedgehog, fowl and another guinea pig caused edema. This 

 was not due to epinephrin because suprarenals of the cat and dog failed 

 to produce the effect. On the other hand, although guinea pig suprarenals 

 were irritating for other guinea pigs, they produced no inflammation in 

 the rabbit, cat or rat. This peculiar susceptibility of the guinea pig is 

 unaccounted for. The available evidence indicates that suprarenal substi- 

 tution by means of grafts is possible but difficult. 



Reaction of the Suprarenals to Various Factors 



Response to Toxins. The suprarenals respond to many infections in 

 such a way that it has been suggested that they exercise an important part 

 as a detoxicating mechanism. An extensive consideration of the evidence 

 would lead us too far into the domain of pathology; we propose merely 

 to touch upon the problem. 



It is known that many intoxications if prolonged induce hypertrophy 

 'of -the suprarenals and especially of the cortex. Frequently in these cases 

 the epinephrin content is lower than normal. Porak(a) has studied the 

 effect of infection with rabies, tetanus, poliomyelitis, diphtheria and pneu- 



