POISONOUS PLANTS 199 



Of exotic species cultivated in Britain, mention must be 

 made of Cytisus Laburnum, the laburnum-tree ; varieties of 

 Lupines grown as ornamental plants and also sometimes for 

 forage ; and Trifolium hybridum, or alsike clover, grown for 

 forage. Definite cases of poisoning by these are well 

 established. The cultivated Coronilla and Wistaria, are 

 reputed to be dangerous, but are not important. 



Exotic species, the seeds of which have been used as 

 forage, and which are definitely and seriously poisonous, are 

 Lathyrus sativus, the Indian pea, and Phaseolus lunatus (see 

 under Cyanides). 



Laburnum. 



Cases of poisoning by laburnum are not numerous, nor 

 are the records of our literature satisfactory. Cornevin, 

 however, has submitted the question to experimental test 

 and established the toxicity of the plant beyond doubt. 

 Moreover, poisoning in the human subject, usually by 

 eating the flowers, is well recognised. 



Active Principle. — The active principle, possibly not the 

 only agent, is the alkaloid cytisine. All parts of the plant 

 are poisonous, the greater part of the poison being, however, 

 found in the seeds. Desiccation does not destroy the 

 activity, and the poison is not entirely removed from the 

 seeds by boiling. 



EfTects. — Cornevin found it impossible to kill the dog or 

 cat by feeding (on account of vomition) ; or the sheep, 

 goat, or ox by reason of refusal, after a certain point, of the 

 food. The horse and ass could be killed by feeding, and all 

 animals by injection of the poison. Taylor records, simi- 

 larly, failure to poison the dog and cat. 



Vomition, excitement, followed by clonic contractions 

 and coma, appear to be produced in carnivores. 



In the horse Cornevin observed general and sexual excite- 

 ment, muscular tremors, followed by contractions, beginning 

 in the posterior parts. In general the poisoning is in three 

 stages — (1) excitement ; (2) coma and inco-ordination of 

 movements ; (3) convulsions. 



