ni] Papilionaeeae 33 



lunatus are poisonous, and the fact is noted by Church {Food Grains of 

 India, 1886), and by Watt {Dictionary of the Economic Products of 

 India, 1889-96). The coloured forms, and particularly the wild forms, 

 are the most dangerous, the white types being in general safe for 

 stock feeding. Some forms have a general similarity to butter beans 

 and haricots, and have hence been favourably regarded by farmers, but 

 it is a sound plan to purchase under a guarantee beans with such names 

 as those given. 



Toxic Principle. It was shown in 1903 {Proc. Roy. Soc, Vol. 72) 

 that the seeds of P. lunatus, uncultivated in Mauritius, contained a 

 cyanogenetic glucoside, Phaseolunatin (CioH^^OgN). This glucoside, 

 under favourable conditions, such as are present when the beans are 

 moist, masticated and ingested at the temperature of the animal body, 

 gives rise to prussic acid, which is the direct cause of poisoning. The 

 seeds of the wild forms yield, hke bitter almond seeds, considerable 

 quantities of prussic acid, while the cultivated forms resemble sweet 

 almonds in yielding only traces of the acid, or none at all. Deter- 

 minations of the yield of prussic acid by various investigators show 

 percentages of from 0-027 to 0-137 in Java beans, and 0-004 to 0-02 

 in Burma beans. The largest proportion therefore occurs in the coloured 

 beans, while the white forms contain much less or none at all, and may 

 be generally regarded as safe for stock. 



Symptoms. — The symptoms given by Damman and Behrens {Veter- 

 inary Journal, 1906) were vertigo, tympany, and falling, with death in 

 most cases. Mosselmann {Vet. Jour., 1908) observed the symptoms 

 due to the ingestion of a small quantity of the beans by six head of 

 cattle. They were: great excitement, salivation, swelling, sHght 

 diarrhoea, quick pulse and respiration, muscular spasms, and paralysis 

 of the hind quarters in one instance ; all recovered rapidly. 



REFERENCES. 



5, 38, 76, 77, 107, 109, 125, 129, 144, 255. 



Castor Oil Plant {Ricinus communis L.). The beans (see Frontispiece) 

 of this exotic are toxic, and poisoning is only likely to occur if they are 

 sold in error as a feeding stuff, or from the use for feeding purposes of 

 the press-cake after the extraction of the well-known castor oil, a pur- 

 gative commonly used medicinally, of which the beans contain about 

 50 per cent. According to Cornevin four seeds sufl&ce to cause accidents 

 in man, eight lead to very grave results, and beyond that number death 

 may ensue. Pigs and poultry have been poisoned by the seeds, and 



L. 3 



