THE JOURNAL OF PHARMACOLOGY. 



traeger's reaction for aloin is not, correctly speaking, a reaction for aloin 

 but for emodin ; aloin that has been deprived of eniodin not giving the 

 reaction. A test of the emodin obtained from Barbadoes aloes showed 

 that in doses of half to one grain it possesses marked purgative properties, 

 and in smaller doses quite marked laxative properties, and it was shown 

 that this property is due to increased peristalsis of the intestine. It was 

 further shown that solutions of pure aloin, when allowed to stand exposed 

 to the air, develop in a very short time quantities of emodin which were 

 isolated and analyzed. The same result can be obtained by heating aloin 

 with a i per cent, solution of caustic potash. Whether the reaction is one 

 of oxidation or of saponification has not yet been determined, but it is be- 

 lieved that the laxative properties of aloin are due to emodin, and that 

 even if our aloin that has been deprived of all emodin is taken into the 

 system the conversion of the same into emodin in its passage through the 

 system is the cause of its lazative property. 



While this does not detract from the value of aloin, it much increases 

 our interest in this substance, and accounts for the unusual efficacy and 

 popularity of cascara sagrada, whose active principle, the glucoside pur- 

 shianin, which it was my good fortune to be the first to isolate, does, as 

 we know easily by saponification, split up into sugar and this same emodin. 



The result of this valuable contribution to pharmaceutical science of 

 Professor Tschirch and his pupil, G. Pedersen, will be to stimulate the 

 interest in emodin, and probably to give us a ready means of making it on 

 a large scale. 



To sum up the points brought out in this paper : i. That Curacoa aloes 

 is as efficient, and, being much cheaper, should be used in preference to 

 Socotrine aloes, the greater portion of which, as sold to-day, is made up any- 

 way of Curacoa aloes. 2. That the resin of aloes is an ester or organic 

 salt, and varies according to the kind of aloes, and that the varying con- 

 stituent is the acid, the alcoholic constituent being aloresinotannol and 

 being the same in both Barbadoes and Cape aloes, the only two thus far 

 examined. 3. That aloin contains emodin, to which its laxative property 

 is probably due. 4. That many laxative drugs, such as senna, cascara 

 sagrada, rhubarb, buckthorn bark, besides aloes, owe their laxative prop- 

 erty to this substance emodin or some substance like it, derived from 

 anthraquinone, and homologous or isomeric with it. 



Work is now in progress to show the exact relation of anthraquinone to 

 our well-known laxatives. — Druggist's Circular, September, 1898. 



