822 the r6le of nitrogen, ETC., I., 



Schulze(70) found in peas, oats, and flax; vicine in Vicia sativa 

 and V. Faba; the three lupine alkaloids lupinine, lupinidine r 

 lupanine; and many others. 



The vegetable alkaloids are built upon the structures of certain 

 well known hetero-cyclic bodies — pyridine, quinoline, and acridine. 

 Very little is actually known of their antecedents in vegetable 

 metabolism, but here again Latham(71) has given us some valuable 

 suggestions of possible methods by which we can trace their 

 relation to the proteins. By starting with acetic acid and pass- 

 ing through the cyanide stage, we can obtain pyruvic acid, 

 CH 3 COC00H ; the latter condenses with hydrocyanic acid,, 

 ammonia, aldehydes, etc., to form amino-acids, amides, pyridine, 

 quinoline, pyrrol and indol. Quinoline-derivatives may also be 

 obtained by the union of certain aldehydes with amino-benzal- 

 dehyde, which suggests that benzaldehyde may be a constituent 

 of living protein. 



7. The glucosides containing nitrogen are mainly the cyano- 

 genetic compounds, and these have a far wider distribution than 

 is commonly believed, if it be accepted that they are the only 

 precursors of hydrocyanic acid in plants. The latter has been 

 produced from considerably over a hundred different plant-species, 

 many of which are of great economic importance, such as cassava, 

 sorghum, vetches, maize, beans, seeds of para-rubber tree, etc. 

 Out of the vast number of plants in which cyanogen occurs, only 

 a very few glucosides have been isolated and their constitution 

 made known. The chief of these are — 



Amygdalin(72) from almonds and the seeds of a number of 

 other plants. 



Sambunigrin(73) from the elder-berries. 



Dhurrin(74) from the sorghum or Indian millet. 



These three, when hydroh sed, split off hydrocyanic acid, benzal- 

 dehyde, and sugar. 



Phaseolunatin(75) from Phaseolus lunatus (Lima-bean), flax and 

 cassava. This yields hydrocyanic acid, acetone and glucose. 



Lotusin(76) from the lotus-plant of the Nile, and also from the 

 Lotus aitstralis. In this glucoside alone, the sugar is directly 



