POISONOUS PLANTS 



291 



them the number of animals were not stated, but at the 



other six 133 head of 



cattle were involved, and 



of these no fewerthan 43 



died. The meal on which 



the animals were fed was 



prepared from the beans 



of P. lunatus, of which 



several types occur in 



cultivation and in the 



wild state. These types 



exhibit Considerable dif- FlG " 79.-Java Beans, nat. size. 



ferences in colour, some of them being creamy-white, 



reddish-brown, brownish with 

 purple spots and blotches 

 (Fig. 796), purplish-black, or 

 black with white stripes. 



The toxic principle is Phaseo- 

 lunatin, a glucoside which, 

 under certain conditions, gives 

 rise to prussic acid. The 

 largest proportion of the 

 poisonous principle appears 

 to be contained in the coloured 



seed beans ; the white forms (Fig. 



79^:) contain much less, or none 



at all, and are in general safe 



for feeding to stock. Before any 



doubtful kinds of beans are used 



for feeding purposes their identity 



should be ascertained, and they 



should be purchased under guaran- 

 tee. (See the Journal of the Board 



of Agriculture for March and April 1906, and March 



By courtesy of the Editor of The Field. 



FIG. 79*5*. Red Rangoon Beans, 

 nat. size. 



FIG. 7gc*. White Beans, 

 nat. size. 



