Dec. 189-1.] BOTANICAL SOCIETY OF EDINBUKGH. 309 



As with man so with horses, the lathyrus is a cumula- 

 tive poison, the symptoms of poisoning showing themselves 

 the sooner the greater the proportion of L. scUivus seeds in 

 the horses food. Principal M'Coll states that 2 lbs. a day 

 could be continued for six weeks or so before symptoms of 

 attack showed themselves, while, at Liverpool, the Messrs. 

 Leather fed 4 lbs. or 5 lbs. a day out of 20 lbs. of grain 

 for three months. There is generally a certain proportion 

 of horses that do not seem to be affected. Indeed, it is 

 curious to learn from the evidence in the Bristol Tramway 

 Company case that corn merchants in different parts of the 

 country were in the habit of buying quantities of Z. sativus, 

 and that having sold it in mixtures for horses in proportions 

 varying from two to ten per cent., they had received no 

 complaints. As far as experimental evidence is obtainable, 

 such would seem to show that boiling the seeds before use 

 renders them innocuous. 



In a number of cases dealt with in Glasgow and 

 neighbourhood, 100 bolls of the L. sativus seeds lay un- 

 used for some time until by Principal M' Coil's, orders 

 they were boiled, steamed into a pulp, and when fed in 

 quantities of 1| lbs. per night per horse, no bad effects 

 followed. 



Watt in his valuable article points out that there is a 

 " certain capriciousness " in the effects of the poison on 

 different individuals, and, adopting the view that the 

 poisoning effects are due to a volatile alkaloid, he suggests 

 that persons eating cakes made from Z. sativus grain do 

 not suffer, as all parts of the cake being thoroughly exposed 

 to a high temperature the poison is eliminated, whereas in 

 food preparations exposed to only a moderate temperature 

 sufficient of the poison remains to act injuriously on those 

 partaking of such foods. 



In the examples quoted as to injury to human beings in 

 India and to the horses in Liverpool, Glasgow, and Bristol, 

 the small dark coloured seeds caused the harm. But there 

 have been frequent references lately to horses showing the 

 same kind of attack on being fed with mixtures containing 

 the larger white-coloured seeds of Z. sativus, weisse, the 

 so-called '•' dog-tooth vetch," in Bedlington, where a 

 number of mine ponies suffered, at Eastwood 20 to 30 



