154 PLANT PRODUCTS 



and made into a paste with water. The mixture is thoroughly 

 dried, powdered, and extracted with chloroform, ether, etc. 

 The alkaloids are removed from the solvent by agitating 

 it with dilute acid, and then precipitated by ammonia. 

 The alkaloids thus obtained are chiefly composed of quinine, 

 hydroquinine. cinchonine, cinchonidine, and a little quinidine. 

 Crude alkaloids of this nature are not infrequently employed 

 as medicine, especially in India, where they may be sold 

 under such titles as cinchona febrifuge, sometimes misnamed 

 by the natives as cinquinine. A nearly complete separation 

 of the quinine may be effected by taking advantage of the 

 small solubility of quinine in cold water. Qiiinine is a 

 fairly strong base, giving two sets of salts, mono-acid and 

 di-acid. 



Nicotine. — Nicotine is prepared chiefly from the tobacco 

 leaf, mid-ribs, and waste tobacco, and from the liquors which 

 are by-products of tobacco intended for chewing purposes. 

 These materials are extracted with water, and the liquor 

 concentrated. After the addition, steam distillation gives a 

 liquor containing a crude form of nicotine. This is acidified 

 with oxalic acid, and evaporated to a small bulk, subsequently 

 decomposed by potash, and the nicotine floats on the surface, 

 and is separated mechanically. Waste tobacco and crude 

 forms of nicotine are largely used as insecticides, especially 

 for horticultural work. 



Tobacco. — Tobacco can be grown in the British Isles 

 where the cool moist temperature on the west coast makes the 

 tobacco plant fairly independent of variations of soil moisture, 

 which is such an important point in all tobacco-growing 

 districts, and perhaps accounts for the fact that on the west 

 coast of the British Isles small degrees of frost are not found 

 to be fatal, whilst on the European continent a frost is con- 

 sidered a fatal difficulty. Any good soils can be made 

 suitable by tillage for the production of tobacco, but the 

 plant flourishes best in a fairly open soil, which is well 

 supplied with organic matter. 



Tobacco is especially sensitive to the amount of lime in 

 the soil. Continental practice considers that the amount 



