It has long been known that beans of certain forms of _Phaseolus 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_ (C_{10}H_{17}O_{6}N). 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, like 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. Determinations 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 (_Veterinary 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, slight diarrhœa, 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 purgative commonly used medicinally, of which the beans contain about 50 per cent. According to Cornevin four seeds suffice 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 M. Audibert (near Beaucaire) reported the death of 80 sheep from eating the press-cake, which is stated to have more pronounced properties than the oil. It has been found as an impurity in linseed cake and maize meal. (_Jour. Roy. Agric. Soc._, 1892.)