68 THE USES OF PLANTS, 



duced comparatively lately. It is one of the most 

 costly vegetable productions ; but Professor Morren's 

 discovery in 1837 that the flowers of the various 

 orchids of the genus ( Vanilla planifolia, Andrews, etc.), 

 from the placentae of which the odorous substance 

 is obtained, could be artificially fertilized* has enabled 

 them to be successfully cultivated throughout the 

 tropics. They owe their value to I per cent, of 

 vanillin, C 16 H 8 O 6 , a feebly acid, crystalline substance, 

 the nature of which was demonstrated in i858.f In 

 1874 this substance was prepared by Tiemann and 

 Haarmann from Coniferin (C 16 H 22 O 8 + 2H 2 O), a com- 

 pound first observed by Hartig in 1861 in the cambium 

 of various conifers.^ Coniferin is now largely collected 

 in Continental forests and manufactured into vanillin. 

 This substance has also been recently obtained from 

 asafcetida. A former substitute for it was the Sassa- 

 fras-nut, Puchury or Pichurim-bean, the large cotyle- 

 dons oiOcotea Pichurim, H. B. K. (NectandraPuchury> 

 Nees) of the Rio Negro. || 



(4) Alkaloids. 



Undoubtedly the greatest service which chemistry 

 has rendered to medicine during the present century 

 has been the extraction from many vegetable sub- 

 stances of those crystalline, nitrogenous bodies known 

 as alkaloids, by which exact doses of known character 

 can be experimented with in a state of isolation, or 



* ' Annals of Natural History,' iii (1839), p. i. 



t Gobley, * Journ. de Pharm.,' xxxiv (1858), p. 401. 



% ' Pharmacographia,' p. 597. 



' Archivd. Pharm.,' June, 1886, p. 434. 



II Archer, ' Econ. Bot.,' p. 94 ; 'Pharmacographia,' p. 485. 



