154 CORTEX 



interior of the abdominal vena cava. Whether this was its 

 original site or whether it developed from cellular masses 

 accidentally implanted during resection of the vessel is de- 

 batable. 198 



The above described results indicate that the generally 

 accepted view regarding the frequency of the existence of 

 scattered cortical tissue in the rabbit is erroneous. Complete 

 removal is difficult ; but it is unnecessary to assume that tissue 

 capable of supporting life exists along the vena cava and is 

 diffusely scattered throughout the dorsal peritoneal spaces or 

 in the reproductive organs, as claimed by a number of in- 

 vestigators. 



Guinea pig. The guinea pig is ill-suited for adrenalectomy. 

 It is extremely sensitive to any surgical manipulation and 

 hemorrhage, and hence in the hands of most experimenters 

 death has followed adrenalectomy in this species within a few 

 hours to a day following operation. To add to the difficulty, 

 the right gland is intimately connected to the vena cava. As 

 in the rabbit, one risks a fatal hemorrhage or the possibility of 

 leaving glandular tissue behind, which, in surviving animals, 

 hypertrophies and allows extended survival. The guinea pig 

 like the rabbit should be avoided for experiments involving a 

 complete adrenalectomy. 



Dog. The dog, because of the many advantages it offers as 

 an experimental animal, has been the subject of numerous 

 studies on the effects of adrenalectomy. It is comparatively 

 easy to perform the operation so as to remove all the gland. 

 Accessory tissues are rarely present or, at least, are removed 

 with the connective tissue surrounding the main glands, for 

 rarely do the animals survive for extended periods as in the 

 case of the rabbit or rat. 



Adrenalectomy in dogs is best performed by the lumbar 

 approach. The smaller species are more easily adrenalec- 

 tomized than large fat animals in which one has to penetrate 



