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 boiling the seeds before use renders them innocuous. Lathyrism 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 different samples, owing to differences in soil, climate, and other factors. In man, Lathyrism 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 cyanogenetic 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 is paralysis of the hind limbs, dyspnœa and roaring—with paralysis of the recurrent laryngeal nerve, and transverse myelitis. The horse thus shows weakness of the hind quarters, staggering in the effort to stand, difficulty in breathing, abnormally fast and irregular pulse, open mouth, distended nostrils. Tracheotomy often gives almost immediate relief.