53 



v x 



and cells we see when plants are microscopically and even macroscopically 

 examined. In the infancy of chemical science it was customary to call 

 in the aid of the vital principle in further explanation. It seems that 

 we have now got beyond that ; " nous avons change tout cela " as the 

 French say. I shall have, however, something more to say about this 

 point before I close this lecture. 



But those albuminoids are not the only compounds which plants are 

 capable of forming with such inorganic nitrogen ; many very wonderful 

 compounds of different nature are stowed away in the root, stems, leaves 

 and seeds of plants and trees which have nitrogen for an essential 

 constituent. They are known as the alkaloids so much used in 

 medicine. Although the plants and trees which yield the alkaloids 

 grow in localities wide apart, ai different altitudes, on soils of varying 

 composition, and although they frequently come from very different 

 parts of the plant, from the roots, the stem, the ban<, the sap, the 

 leaves and the seed, yet the fact that plants cannot elaborate these 

 curious and valuable and dangerous substances without nitrogen, 

 ammonia or nitric acid is common to them all. Among them are 

 caffeina, which in tea, coffee and cocoa cheers, but not inebriates '> 

 quinia, the great fever remedy, from the bark of shrubs and trees of 

 the tribe cinchonacea; growing on the west slope of the Andes 

 morphia, from poppy juice, well known for its sedative powers and 

 regarding which it has been remarked that by its judicious employment 

 more happiness and by its abuse more misery has been produced than 

 by any other drug used by mankind. Aconitia, mostly used in the 

 anodyne liniment, seems to be to the human body outwardly what 

 morphia is internally, a soother of pain. But it as well as atropia, 

 brucia and strychnia are also known as the most powerful poisons. 

 They are in appearance very innocent individuals, but they are 

 terribly dangerous at close quarters. 



The following formulae show the composition of some of these 

 bodies : 



Caffeina C g H lu N 4 0,+ H,0- Atropia C 17 H N 3 . 



Quinia C, H, 4 N, O, + 3H.A Brucia C H a; N, O,. 



Morphia C 17 H 1(1 N S + H U 0. Strychnia C H N, 0. 



Aconitia C-H J:j N O i2 . 



