GROSS ANATOMY 35 



represent most probably hypertrophied nodules similar to those 

 often encountered in other secretory glands. 



The term accessory adrenal is applied to small islets of tissue 

 which are present in the fat and connective tissue surrounding 

 the adrenal glands. These islets are for the most part micro- 

 scopic in size except in large animals such as man, the horse or 

 cattle. In the last named they frequently attain the size of a 

 walnut. In the cat, rabbit, or dog they are occasionally 

 visible to the naked eye, but in the rat or mouse they can only 

 be detected in microscopic sections. These accessories at 

 times are said to resemble the main gland in their histological 

 arrangement and contain chromaphil tissue in their medulla. 

 For the most part, however, they consist of cortical tissue only 

 the cells of which resemble in their arrangement those of the 

 Stannius corpuscles of the Teleost fishes (cf. Figure 6) . 



In Figure 3 is reproduced an adrenal of the cow containing an 

 accessory body which projects like a wart from the surface of 

 the gland. This type of accessory is in reality merely an hyper- 

 trophic nodule which has formed near the surface of the gland. 

 In Figure 3 are also reproduced two discreet accessory adrenal 

 bodies obtained from the connective tissue surrounding the 

 main glands. These represent true accessory bodies. On 

 cross section they are found to be composed of cortical tissue 

 arranged in columns resembling the fascicular layer of the 

 main gland. 



The accessory adrenals situated in the vicinity of the adrenals 

 are commonly found in most animals. Although said to occur 

 with greater frequency in some species than in others, this 

 view is based on indirect evidence derived from extirpation 

 experiments. Thus the accessories are said to be relatively 

 uncommon in the cat or dog because adrenalectomy is fatal 

 in these animals. In the mouse, rat, or rabbit, however, the 

 presence of accessory adrenals is considered to be very common 

 because these animals often survive adrenalectomy. As a 

 matter of fact, even in these animals, meticulous care in 



