THE SUPRARENAL SYSTEM 253 



and wedge-shaped granules which are arranged in a peculiar 

 manner in the protoplasm, and which stain black with iron 

 hcematoxylin. But the biological significance of these bodies, 

 that is to say, their relationship to the secretory process, is by no 

 means clear. 



According to Stoerk and v. Haberer, the process of the secre- 

 tion of adrenalin takes place in the following manner : the chrome- 

 brown secretion is formed by the fine granules, which become 

 gradually more heavily charged until a certain secretory climax 

 is reached, when the chrome-brown secretion is discharged into 

 the intragranular cytoplasm. The cytoplasm, which is character- 

 ized by its pronounced affinity for basic aniline dyes, becomes 

 saturated with the chrome-brown secretion and, at this stage, 

 yields the diffuse ferric chloride reaction. The nuclei of the 

 adrenalin-forming cells are distinguished by their small provision 

 of chromatin, and by their peculiar situation at that cell-surface 

 which is farthest removed from the vein against which the cell 

 is situated. They sometimes react to chromium, which suggests 

 that they also are saturated with the secretion. 



When the cell contents have, up to a certain point, become 

 saturated with the secretion, the latter gradually becomes diffused 

 through the cell membrane and the capillary wall into the blood. 

 At the same time, the cytoplasm and the granules gradually cease 

 to react to chromium, and the process starts afresh. It appears 

 from this that, if classified according to the nature of its secretory 

 processes, the adrenal system belongs to the group of meroendo- 

 krinal glands (Poll). 



After its transference from the cells to the blood-stream, the- 

 substance is easily recognizable in the capillaries by its yellow- 

 brown coloration. Its tardy solubility in serum, and certain 

 microscopic appearances, give it a certain resemblance to the 

 mucous type of secretion. This adrenal substance is characteristic; 

 of the vessels of the suprarenal medulla, and is found neither in 

 the vessels of the cortex nor in other vessels. It is distinguishable 

 by its peculiar refractivity in native preparations, and was formerly 

 observed in the venous blood of the suprarenals as a plastic mass 

 (Gottschau, Biedl). It was at that time erroneously believed that 

 the granules in this amorphous mass were the actual secretion. As 

 Stoerk and v. Haberer sho\ved, these shining granules are not 

 identical with the chrome-brown granules, though their functional 

 significance is, up to the present, not clear. 



It may be regarded as proved that the product of the adrenalin- 

 producing cells reaches the blood-stream in fluid form. Stilling 

 supposes that the transference of the viscid secretion is effected 

 by means of the numerous and important lymphatics; but in this 

 he is wrong, for this function is performed by the veins. The 

 suprarenal vein plays the part of excretory duct to the medullary 

 substance of the suprarenal. 



