THE SUPRARENAL SYSTEM 279 



paratively non-toxic substance and, as Blum pointed out, in doses 

 of .6 to 2 mg. per kilo of body weight, produces only a transitory 

 increase in blood-pressure, and has no effect whatever upon 

 the secretions. I was able to convince myself that Modrakowski 

 was right in his findings, and they have since been confirmed by 

 Busquet and Pachon. A pure cholin which was prepared by my 

 colleague, S. Fraenkel, when injected into the veins of dogs in 

 quantities of 4 mg. to every kilo, produced a distinct, though very 

 transitory, increase in blood-pressure. After being kept for a few 

 days, the preparation acquired a distinct odour of trimethylamin, 

 and in doses of even 2 mg. produced marked hypotension and 

 slowing of the pulse. After atropine, a fresh injection of the 

 substance produced slight hypertension. This substance proved, 

 after keeping, to be actively toxic, for animals into which it was 

 injected in doses of i mg. per kilo died within a few hours. 



According to these findings, then, cholin is neither specific to 

 the suprarenal cortex, nor is its action antagonistic to that of 

 adrenalin. 



The suprarenal contains yet other substances, the importance 

 of which to the vital processes has only recently been discovered. 

 These are the lipoids. The presence of fat and substances similar 

 to fat is mentioned in some of the older writings upon the supra- 

 renals, but at that time our knowledge of the chemistry of these 

 substances was very scanty. It is only recently, and indeed very 

 recently, that we have arrived at any definite knowledge of the 

 nature of the lipoids. The interest which has been aroused in 

 both physiologists and pathologists by the lipoid substances in 

 general, has drawn a certain amount of attention to those of the 

 suprarenal in particular. 



I have occupied myself with researches in which I made use 

 of the most recently discovered chemical methods into the nature 

 of the lipoid substances; and, in so far as my results concern the 

 lipoids present in the suprarenals, they may be given here. In 

 order fully to understand these results, it is necessary briefly to 

 explain the older views, based almost entirely upon histological 

 and biochemical material, and to show the manner in which recent 

 chemical science has modified our views concerning the nature of 

 the suprarenal lipoids. 



It has long been known to morphologists that the suprarenal 

 cortex, or rather the entire interrenal system, occurring in verte- 

 brates of whatever species, possesses a remarkable cytological 

 peculiarity, namely, the presence in the cells of fat-like 

 lipoid granules, from which the name ' lipoid tissue," used 

 to describe the interrenal tissue, is derived. However much the 

 structure and arrangement of the interrenal system may vary 

 and according to H. Poll these variations are constant in mam- 

 mals of the same species the lipoid granules, or cortical granules 

 as they are called, are a constant and characteristic feature both 



