THE SUPRARENAL SYSTEM 151 



adrenal bodies, formerly called the "axillary heart," cannot be 

 removed. Conditions relatively more favourable for extirpation 

 are offered by the interrenal system. 



The interrenal body of sharks (Squalidae) is a long narrow 

 band, situated between the kidneys and partly covered by 

 them ; it is continued towards the cranium as a detached band, or 

 in separated dot-like bodies. The interrenal body is exposed by 

 raising the kidneys from the dorsal abdominal wall. In some 

 species of Squalida?, the interrenal body is embedded in the sub- 

 stance of the kidney and is only visible in preparations. I em- 

 ployed small specimens of Scyllium cattulus and Scyllium canicula 

 as subjects for my investigations, and in twelve cases I succeeded 

 in removing the interrenal body. Of these, one lived for eight 

 and one for ten days, while the remaining animals lived for three 

 weeks, after which they were destroyed. Anatomical examination 

 of the first two animals showed an entire absence of interrenal 

 tissue. In all the other cases, post-mortem examination showed 

 remnants of interrenal tissue of a varying size, which upon histo- 

 logical examination were found to be hypertrophied. 



Experiments with Raiidag (skates and rays) were more in- 

 structive, and the anatomical conditions were decidedly more 

 favourable. In most Raiidas, round or oval paired bodies are 

 found to right and left of the middle line between the kidneys ; 

 occasionally they are united by a bridge of varying width. In 

 the species which I employed (Torpedo marmorata, T. occellata, 

 Raia batis, R. punctata, R. clavata), there is generally a largish 

 interrenal body, situated either to right or left, generally at the 

 caudal point of union of the kidneys; while upon the other side, 

 more in a cranial direction and at the medial border of the 

 kidneys, a row of smaller bodies is sometimes found. For anyone 

 who is acquainted with the anatomical conditions it is possible to 

 remove the whole of the interrenal tissue ; care must be taken, how- 

 ever, to avoid any isolated interrenal bodies which may be present. 



In twenty-seven cases out of thirty-two, post-mortem examina- 

 tion revealed no trace of interrenal tissue ; in one case there was 

 a portion of about the size of a grain of millet seed, and in four 

 cases portions as large as a pea. Animals which died within 

 forty-eight hours were excluded, for these cases always showed 

 changes which sufficiently explained the cause of death. Apart 

 from violent haemorrhage and destruction of the renal tissue, the 

 severing of the abdominal sutures and consequent prolapse of the 

 viscera was the most frequent cause of death. In successful cases, 

 for the first three to four days after operation, there was no 

 appreciable change in the condition of the animals, the first sym- 

 ptoms making their appearance at about the seventh or eighth day. 

 The .animals first showed a loss of liveliness and readiness to move 

 about ; spontaneous swimming about the aquarium became less 

 frequent ; and, compared with control animals in the same 



