28 PapiUonaceae [ch. 



14 recovered. In the famous Bristol Tramways case (1894) 123 out of 

 800 horses became ill owing to being fed on the peas of L. sativus, and 

 many died. There are few records of harm to cattle, sheep and pigs, 

 and Watt quotes Don to the effect that pigeons lose their power of 

 flight by feeding on the peas. Very large quantities of the peas are used 

 for feeding purposes, and the fact that the losses are not larger is 

 probably because the peas only comprise a small proportion of the 

 ration or are cooked before use. 



After boiling or roasting the peas appear to be less harmful, as they 

 are eaten in India when cooked, or ground into flour and converted into 

 bread — though Cornevin states that drying and cooking does not 

 destroy the toxicity, while boiling for some time showed that at any 

 rate part of the toxic substance passed into the water, which became 

 toxic and caused death, the boiled seeds losing the greater part of their 

 poisonous property and not causing accidents when the water was 

 rejected. MacDougall states that as far as experimental evidence was 

 available (1894) it seemed to show that boiUng the seeds before use 

 renders them innocuous. 



Lathryism usually only supervenes when the use of the peas for food 

 is prolonged, and the peas are taken in considerable quantity, but 

 it is possible that there is wide variation in the toxicity of difierent 

 samples, owing to differences in soil, climate, and other factors. In man, 

 Lathryism is stated to be common in Spain, Italy, Russia and India, 

 owing to continued use of bread from flour of the three species of Lathyrus 

 mentioned above. It is said especially to affect males. 



Toxic Principle. Nothing certain as to the poisonous properties is 

 known, attempts to isolate the toxic substance having failed (Kobert), 

 though Smith gives it as prussic acid, apparently indicating a cyano- 

 genetic glucoside. This, however, can hardly be so, as the poison is 

 cumulative, and may not show its effects for weeks or months, or, in 

 man, even years — according to the quantity of peas eaten. 



Symptoms. Lathyrism is only produced when the ration consists 

 largely of the pea for a considerable period (see above) ; in the horse 

 fed exclusively on the pea, the tenth day ; but when one or two quarts 

 are given daily, only towards about the 80th day. Moreover, the malady 

 may declare itself as long as fifty days after the cessation of the pea 

 feeding (Lander). 



In general Lathyrism is marked by paralysis of the lower extremities 

 in man and the hind limbs in animals, owing to the degeneration of the 

 muscle fibres, and possibly to affection of the nerves. In horses there 



