152 BRITISH PLANTS 



(c) Drugs. Hundreds of drugs used in medicine are 

 prepared from plants poisons, antiseptics, narcotics, 

 anaesthetics, etc. all capable of producing more or less 

 profound disturbances in the physiological activities of 

 the human body. Peruvian bark, or Cinchona, is the 

 source of quinine, the opium-poppy the source of laudanum 

 and morphia. Tobacco may be regarded as a mild drug. 



Industrial Economic Plants include such as provide 

 timber, paper, straw, cane, fibres (cotton, jute, hemp, 

 flax), gums, resins, oils (palm, olive, linseed), turpentine, 

 pigments (madder, indigo, saffron, logwood, turmeric), 

 camphor, rubber, and guttapercha. 



In fact, man is dependent upon the vegetable world for 

 much of his food and drink, his luxuries, the materials 

 to clothe him, and for countless products which serve 

 directly or indirectly to satisfy his needs. 



Poisonous Plants. Many plants contain principles 

 which act as poisons to man. These poisonous substances, 

 however, are not necessarily poisonous to all animals. 

 Thus, the thrush eats the berries of the cuckoo-pint ; and 

 every succulent fruit, however poisonous it may be to 

 others, must be eaten with impunity by some birds (p. 136). 

 Drugs are, in a sense, only mild poisons. The following 

 plants, growing in England, have been used at one time 

 or another in medicine : buckthorn, broom, cherry- 

 laurel, hemlock, woody nightshade, foxglove, rhubarb, 

 spurge-laurel, chamomile, gentian, valerian, dandelion, 

 nettle, etc. 



Folk-lore has associated benignant properties with 

 many plants which are quite innocent of any medicinal 

 value, good or bad. Some possessed magical qualities, 

 and were used in enchantments. 



