840 



5. " On the Nitrogenous Principles of Vegetables as the sources 

 of artificial Alkaloids." By John Stenhouse, F.R.S. 



After observing that there are few departments in organic che- 

 mistry which during the last six or seven years have attracted more 

 of the attention of experimenters than the artificial formation of the 

 alkaloids, and attributing this fact to the interesting nature of this 

 class of bodies both as regards their well-defined chemical properties 

 and the important medical virtues which many of them possess, the 

 author proceeds to state, that although attempts to form the natural 

 alkaloids, such as quinine, cinchonine, &c., by artificial means have 

 hitherto been unsuccessful, yet chemists have been enabled by various 

 processes to procure artificially a considerable number of true alka- 

 loids very analogous to those which occur in nature. The various 

 methods by which this has been effected, such as by acting on essen- 

 tial oils with ammonia, by the destructive distillation of coal and 

 animal substances, &c., are then enumerated and described. 



It is also remarked as somewhat singular, that while so many other 

 sources have been examined, no attempt should have been made to 

 procure alkaloids from vegetable albumen, fibrine, caseine, &c., which 

 are so rich in nitrogen, and which occur in such abundance in many 

 plants. What renders the neglect of these substances the more re- 

 markable, is the consideration that coal has been one of the most 

 productive sources of the alkaloids, yielding them, as it does, four 

 other bases besides ammonia. Now as coal is universally admitted 

 to be of vegetable origin, and to consist of the remains of a variety 

 of extinct vegetables, the nitrogenous principles of which must be 

 regarded as the sources of the bases which it yields, it seemed to the 

 author not unreasonable to expect, that, by acting on the nitrogenous 

 principles of recent vegetables, the same organic bases as those ob- 

 tained from coal, or at any rate a series of analogous bases, would be 

 obtained in still greater abundance; and it subsequently appeared that 

 this latter expectation was not altogether without foundation. 



From the difiiculty of procuring vegetable albumen, fibrine, &c. 

 in a state of even tolerable purity, those portions of plants (usually 

 their seeds) were selected which contain those principles in the greatest 

 abundance. 



In the first instance, a quantity of Phaseolus communis, or common 

 horse-bean, was destructively distilled in a cast-iron cylinder, and 

 the products collected by means of a large condensing Liebig's appa- 

 ratus. These products closely resembled those obtained from the 

 distillation of bones and other animal matters, comprising among 

 other substances acetic acid, empyreumatic oils, tar, a great deal of 

 ammonia and several organic alkaloids. The crude product was super- 

 saturated with muriatic acid, and the clear liquid decanted after the 

 tar had subsided. The acid liquor was next passed through a cloth 

 filter, which removed the greater portion of the resinous matter. 

 The clear liquid was then poured into a capacious still, and super- 

 saturated with carbonate of soda. When the liquid began to boil, 

 much ammonia was disengaged, and a quantity of oily bases col- 

 lected in the receiver. Their amount increased as the distillation 

 proceeded. These bases were separated from the ammoniacal liquid 



