104 FRANK A. IIARTMAN 



It is Well known that when one suprarenal is removed the other hyper- 

 trophies. Stilling (a) long ago demonstrated that the remaining gland 

 might double its weight. Even a small piece of a suprarenal may grow 

 to considerable size after partial excision of the gland. H. and A. Cris- 

 tiani(a) actually measured such fragments at the time of operation. In 

 the course of several months they . found in some instances that these 

 pieces had grown to more than half the size of a normal gland. 

 Moussu and Le Play cite a case in which one suprarenal was re- 

 moved and four months later the greater part of the other gland was ex- 

 cised. The animal (dog) recovered and remained in perfect health. 

 One year later when the animal was killed the suprarenal fragment was 

 found to have increased to normal size. 



Hypertrophy having been shown to follow partial ablation the next 

 question was to determine whether both medulla and cortex take part in 

 this reaction. Canalis thought that it was confined to the cortex. The 

 findings of Labzine also confirmed this. Elliott and Tuckett, however, 

 state that hypertrophy may occur in either medulla or cortex. In a cat 

 suckling kittens they found an increase in the number of medullary 

 cells. Furthermore they observed in a guinea pig from which one gland 

 had been removed, that the medullary cells were largely responsible for 

 the increased growth in the compensating gland. In the rabbit, however, 

 compensatory cortical growth was much more rapid than in the medulla. 

 It is impossible to say which is the more important, medullary or cortical 

 hypertrophy, yet there is considerable evidence that indicates the latter. 

 For example, it is said that the enlargement to meet the strain of preg- 

 nancy as well as the increase incident to infection is largely in the 

 cortex. 



Differential Effects of Extirpation of Each Component of the 

 Suprarenal. Are both cortex and medulla essential to life ? Theoretical- 

 ly this question should be most easily answered in the fishes for here 

 the two tissues corresponding to the cortex and the medulla of the mam- 

 malian suprarenal are separate. 



Biedl(ry) removed the interrenal cortical body in twelve specimens of 

 Scyllium. It consists of a long" band lying between the kidneys and ex- 

 tending toward the cranium. Two animals died in ten days. In these 

 the interrenal body had been completely removed. The other fish were 

 killed at the end of three weeks. Remnants of interrenal tissue were 

 found in them. 



In the Raiidsc it is possible to remove the interrenal tissue with 

 more certainty. In thirty-two individuals belonging to the Genera. Tor- 

 pedo and Raia, Biedl succeeded in removing all traces of the interrenal 

 tissue from twenty-seven. Although the other five did not die they 

 showed symptoms of interrenal insufficiency. On the other hand the 

 remaining tissue appeared to be hypertrophied. The animals from which 



