144 INTERNAL SECRETION 



do not furnish conclusive evidence as to whether or no the supra- 

 renals are essential to the life of the animal organism. 



A peculiar interest is attaching to the guinea-pig as the 

 subject of experimental epinephrectomy, owing to the fact thai, 

 there is no record of any instance where guinea-pigs survived the 

 removal of both suprarenals ; moreover, it is generally believed 

 that accessory suprarenals are never present in these animals. 

 A. Velich has devoted special attention to the study of the 

 guinea-pig, and he found that, out of 100 animals over the age 

 of six months, only five possessed accessory suprarenals. In each 

 case the structure was extremely small, about 1.5 mm. in diameter, 

 and was placed, in four cases upon the right and in one case upon 

 the left, of the vena cava, at the spot where the renal vein opens into 

 it. He also found that, in young guinea-pigs, after extirpation 

 of one suprarenal there was not only a compensatory hypertrophy 

 of the other together with partial regeneration of the tissue 

 left behind from the extirpated organ, but that accessory supra- 

 renals, 2-3 mm. in diameter, were invariably formed at the right 

 of the vena cava, and that these new structures were entirely 

 composed of cortical tissue. The further development of the- 

 minute accessory suprarenals which frequently consist only of 

 isolated cortical elements after the partial extirpation of 'the 

 principal organs, shows that even these structures are capable of 

 compensatory activity. They are not able, however, entirely to 

 replace the complete suppression of the principal organ, and for 

 this reason total extirpation of both suprarenals of guinea-pigs 

 invariably results in death. 



Experiments have been undertaken quite recently which aim 

 at the destruction of the suprarenals by means of specific cyto- 

 toxins. Several investigators (Bigart and Bernard, Abbot, Yates, 

 Sartirana, Gildersleeve, Van Calcar) have endeavoured to pro- 

 duce an epinephrotoxin or suprarenolysin, but their attempts 

 have been principally confined to a description of the pathological 

 changes which take place in the suprarenals, and little has been 

 added to our knowledge of the function of these organs. A. 

 Bogpmolez recently obtained a suprarenolytic serum from rabbits 

 with the suprarenals of dogs, and from dogs with the suprarenals 

 of cats; he found that the injection of this serum was followed 

 by a marked increase in blood-pressure, a stronger cardiac impulse, 

 an acceleration of the pulse and of the respiration, and later, by 

 a, period of prostration, which was, however, transient. He 

 regards these symptoms as the result of the increased activity of 

 the suprarenals and their consequent exhaustion, and of the 

 medullary substance more particularly. Histological examination 

 showed profound changes in the suprarenals of animals which had 

 been treated with injections of suprarenolytic serum. The proto- 

 plasm of the cells of the medulla had become markedly spongy 

 and vacuolized, and was, in parts, entirely dissolved. Amorphous 

 deposits of basophile substance, which the author regards as 



