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VII. Cyanogenesis in Plants .—Part II. The Great Millet , Sorghum vulgare. 
By Wyndi-tam It. Dtjnstan, M.A., F.R.S., Director of the Scientific and Technical 
Department of the Imperial Institute , and Thomas A. Henry, D.Sc. Lond. 
Received April 24,—Read May 15, 1902. 
In a previous paper, our first communication on this subject (‘ Phil. Trans.,’ B, 
vol. 194 , 1901 , p. 515 ), we have shown that the poisonous effects produced by the 
young plants of Lotus arabicus are due to prussic acid, which is not present in the 
plant as such, but originates in the hydrolytic action of an enzyme, lotase, on a 
glucoside, lotusin. Recently we have examined a large number of plants which, like 
this Egyptian vetch, appear, under certain conditions, to possess poisonous properties, 
and at other times to be innocuous and often valuable as fodder plants or food stuffs, 
with the view of ascertaining to what extent they contain glucosides furnishing 
prussic acid. 
Among the first of these plants we examined was the Great Millet, Sorghum 
vulgare, a plant widely cultivated in tropical countries for the sake of its nutritious 
grain, which in many districts of India is the staple food, known as “ Juar,” of the 
natives. In the West Indies what is apparently the same plant yields the important 
“ Guinea Corn” and in South Africa “ Kaffir Corn.” 
We were informed by Mr. E. A. Floyer, of Cairo, that in Egypt it is well known 
to the Arabs that the green portions of the young plant—the vernacular name of 
which is “ I)hurra Shirshabi”—are poisonous, and that during this period the 
plantations are protected in various ways in order to prevent cattle from feeding on 
the immature growth. It is to be noted that in Egypt the name “dhurra” is also 
applied to a variety of maize which is largely cultivated. 
Mr. Floyer has given us the following account of the plant in Egypt. “ Dhurra 
shirshabi ” is not grown in Egypt as a crop, the yield of corn being too small. It is 
planted chiefly in order to shade the “ Arachis” (ground nut), to which it also affords 
protection in forming a poisonous hedge. The “ thinnings” of the young Millet are 
often strewn around a cultivated crop, and the neighbours are warned to keep their 
cattle off. The poison is most intense when young plants, 1 foot high or less, are 
kept without water for a long time, and such unwatered young plant is highly toxic 
to cows. The plant appears to have been brought to Egypt from Syria, and is now 
grown chiefly at Bir Abu Bala, near Ismailia. The “ fellaheen ” do not plant it. 
( 318 .) 24.10,02 
