THE ADRENAL BODIES 127 



origin and nature of the cortex and the medulla. It will only 

 be possible to refer to some of the more important papers. 



Mitsukuri worked out the development of the adrenal 

 body in the rabbit and in the cat. He concluded that the 

 cortical substance arises from the mesoblast, while the medul- 

 lary substance is derived from the peripheral part of the sym- 

 pathetic nervous system, and is at first placed outside of the 

 cortical substance, becoming transported into the middle of 

 the adrenal body in the course of development. That the 

 cortex is derived from the mesoderm and the medulla from the 

 same blastema as the sympathetic ganglia is now almost 

 universally conceded. 



The cortical substance is developed from the ccelomic 

 epithelium in a region known as the " adrenal zone." The 

 extent of this zone varies in differentVertebrates. In mammals 

 the origin of the cortex appears to be from the ccelomic epithe- 

 lium on either side of the root of the mesentery or a little caudal- 

 wards from the cranial end of the primitive kidney, appearing 

 first as a series of buds which subsequently grow together. 



In regard to the development of the medulla of the adrenal 

 body, it has been ascertained that certain cells derived (along 

 with the sympathetic generally) from the neural ectoderm, do 

 not develop into nerve cells, but into chromaphil cells. In the 

 anamnia below the amphibia, these do not enter into any rela- 

 tions with the cortical elements, but remain as chromaphil 

 bodies or corpuscles. In Amphibia and in the Amniota some 

 of these chromaphil cells grow into the cortical gland and form 

 its medulla. Ultimately these acquire the chromaphil sub- 

 stance. It is stated that in man this is not actually found in 

 them until some little time after birth, but it occurs in the 

 embryo of the ox and the sheep long before birth. 1 



D. Addison's Disease and the Pathology of the Adrenal 



Bodies 



1. Introductory and Historical 



The medical practitioner directs his inquiries towards experi- 

 mental physiology and pathology in order to ascertain how far 



1 Bruni in 1912 described the development of the chromaphil tissues in 

 Rana esculenta. The chief point of importance in this paper is the observation 

 that the chromaphil substance is not derived from the sympathetic, but only 



