152 INTERNAL SECRETION 



aquarium, they were much paler in colour ; fourteen to eighteen 

 days after operation they had become so weak muscularly that they 

 could scarcely be induced to swim at all ; their colour was very pale ; 

 and they lay all day in a corner of the aquarium, refusing all 

 food. Their reaction to stimuli almost entirely disappeared, and 

 at the latest, three weeks after operation they died with all the 

 symptoms of general prostration. Post-mortem examination re- 

 vealed no definite cause of death ; the stomach was invariably 

 empty and the blood pale in colour. 



Of the five fish in which portions of interrenal tissue were 

 accidentally left behind, one lived for over four weeks without 

 symptoms of muscular weakness. It was finally destroyed, and 

 was found to possess an interrenal body the size of a pea. Both 

 in this case and the other four, all of which showed symptoms 

 of suppression of the interrenal function, there was distinct 

 histological proof of hypertrophy of the interrenal tissue left in 

 situ. 



In my opinion, these experiments incontestably prove that 

 the complete destruction of the interrenal tissue is incompatible 

 with the continuation of life; and that death occurs under condi- 

 tions similar to those which follow extirpation of the suprarenals. 



The results of my experiments with cartilaginous fish appear, 

 however, remarkably antagonistic to those obtained by Pettit and 

 by S. Vincent with osseous fish. Both these investigators found 

 that eels lived for months after extirpation of the suprarenals and 

 showed no change in their general condition. They considered 

 that the suprarenals of osseous fish were represented by the cor- 

 puscles of Stannius, situated upon the ventral or dorsal surface 

 of the kidneys and composed exclusively of interrenal tissue. These 

 experiments with eels appeared to contradict the results which I 

 obtained with Selachii, and the discrepancy seemed to me the 

 more significant in view of the careful methods adopted by both 

 Pettit and Vincent and the remarkable unanimity of their results. 

 I was unable to detect the slightest inaccuracy either in their 

 methods or observations, and for this reason it seemed that a 

 repetition of their experiments was hardly likely to yield fresb 

 results. For some time, I was unable to find an explanatioa of 

 this difference in the behaviour of Teleostii and Selachii, but 

 Giaconimi's recent anatomical work has explained the mystery 

 in the most satisfactory manner. Giacomini shows that in the 

 eel, in addition to Stannius's body and the interrenal tissue dis- 

 tributed in its vicinity, which he calls the posterior or caudal 

 interrenal organ, an anterior cranial interrenal system is also 

 present, composed of isolated bodies situated at the anterior edge 

 of the head kidney and attached to both the anterior and posterior 

 cardinal veins. The wide distribution of this anterior interrenal 

 system, together with the large amount of interrenal tissue present, 

 makes it very certain that the removal of Stannius's corpuscles 



