

ANATOMY AND EMBRYOLOGY 335 



of cells, which take a brown color when they are stained with chromic acid, 

 and a green stain with iron chloride. They are termed chromaffin cells. 



From the arteries of the diaphragm, from the aorta, and also from the renal artery, re- 

 spectively, are given off a branch to the suprarenal glands. These form subcapsularly an 

 anastomosis, frorn which the cell columns of the cortex are surrounded by a fine capillary 

 network, and which also continues into the medulla; moreover there are the so-called 

 arteriae perforantes, which run through the cortex and first form a capillary network in 

 the medulla. The suprarenal veins empty into the vena cava. 



True accessory suprarenals that are made up of cortex and medulla are 

 rare. On the contrary accumulations of chromaffin tissue may exist outside 

 the suprarenals. The larger have been termed " par aganglia " by Kohn. 

 Such cell accumulations are found on the carotid artery, in the ganglia of the 

 sympathetic trunks and in the solar plexus, in the left stellate ganglion, on 

 the site of giving off of the left coronary artery and superior mesenteric, at 

 the hilus of the kidney, and along the course of the sympathetic nerves 

 (Zuckerkandl, Kohn). In the adult the total amount of the extramedullary 

 chromaffin tissue is not smaller than the medullary part; in the new-born 

 it is greater. Accumulations of cortical substance can be found at the hilus 

 of the kidney, in the renal substance itself, along the suprarenal veins, and 

 in the internal genitalia. Schmorl found them in 92 per cent, of cases, Weisel 

 in the genitalia of new-born boys in 76.5 per cent. Aichel found them never 

 absent in the broad ligament of new-born girls. Some of these, also, later 

 retrogress. 



Embryological and phylogenetic studies agree with the anatomical that 

 the suprarenal apparatus consists of two independent systems which in the 

 lower classes of animals are arranged segmentally and remain separated per- 

 manently. The chromaffin or adrenal system is of ectodermal origin and is 

 part of the sympathetic. 



Already at a very early period the primitive cells separate into two differ- 

 ent forms, into the primitive form of the sympathetic nerve cells and into the 

 so-called phaeochromoblasts, from which the chromaffin cells originate. The 

 cortical tissue the so-called interrenal system develops from the ventral 

 part of the mesoderm and indeed quite in the neighborhood of that place of 

 the celomic epithelium from which the sexual glands originate; suprarenal 

 cortex and sexual glands are laid out in the Wolffian duct, which explains the 

 topography of accessory suprarenals consisting in cortex alone along the 

 entire way that the sexual glands travel, indeed even in the sexual glands and 

 kidneys themselves (Soulie). During fetal life the suprarenal is at first 

 larger than the kidney, and at birth is about the same size. Already at an 

 early period some of the chromaffin cells have broken through the complex of 

 cortical cells to form the medulla. Through the descent of the genital 

 organs small parts of both systems are displaced. This shows that the 

 former complete physiological independence of both systems later gives place 



