THE SUPRARENAL SYSTEM 277 



gold combination was converted, by means of sulphuretted hydro- 

 gen, into the chloride and was employed in experiments upon 

 animals. The intravenous injection of .01 grm. of neurin chloride 

 into rabbits produced a fall in blood-pressure immediately fol- 

 lowed by a considerable rise. There were at first several strong 

 expiratory movements, followed by a reduction in the respirations. 



That cholin was present in the animal economy had long been 

 know r n, and the nature of its pharmacological activity had re- 

 peatedly been investigated (Gaehtgens, Bohm, Brieger, Cervello, 

 Asher and Wood, Formanek). 



Cholin (trimethyloxethylammonium hydroxyd) : 



CH 2 OH 



CH 3 -N 



formerly called neurin, was first discovered in the bile by Strecker, 

 and afterwards found, as a product of the decomposition of lecithin 

 or of protagon, in watery extracts of the brain, and by Mott and 

 Halliburton, in the cerebro-spinal fluid. The latter authors were 

 inclined to regard the fall in blood-pressure observed by Schafer 

 and Moore after the injection of extract of the brain, and by 

 Schafer and Vincent after the injection of that constituent of 

 pituitary extract which is soluble in alcohol, as an effect of cholin. 

 Osborn and Vincent found that the injection of extracts of any 

 portion of the nervous system produced a distinct temporary fall 

 in blood-pressure. They concede that these extracts contain cholin 

 in small quantities, but they do not ascribe the result to the action 

 of this substance ; for the lowered tension persisted after full doses 

 of atropine, whereas, according to their experiments, the effect of 

 atropine upon cholin is invariably to convert the vaso-dilator action 

 into a vaso-contractor one. Vincent and Sheen next discovered 

 that a substance which reduces blood-pressure is obtainable from 

 muscular tissue of all kinds, as well as from the kidney, liver, 

 spleen, testicles, pancreas, ovaries, lungs, thyroid, thymus, supra- 

 renals and the hypophysis cerebri. Vincent and Cramer showed 

 that watery extracts of nervous tissue contain two groups of sub- 

 stances, both of which, when injected intravenously, reduce blood- 

 pressure. One group dissolves readily, the other is scarcely 

 soluble, in absolute alcohol. The alcoholic solution contains two 

 depressant substances. The action of the one is neutralized by 

 atropine, that of the other is unaffected by it. The alcoholic 

 solution yields a slight precipitate with platinic chloride, and this 

 precipitate, when purified, yields prismatic crystals, the platinum 

 contents of which are 32.8 per cent., which corresponds to the 

 platinic double salt of dicholinanhydride. These observers found 

 no cholin in extracts of the brain, and they are of the opinion 



