1 Ocr., 1902.] QUEENSLAND AGRICULTURAL JOURNAL, 283 
In submitting this, I may take occasion to remark that apparently the authors 
of it (Messrs. W. R. Dunstan and T. A. Henry) have up to the present— being 
engaged in investigating the origin of cyanogen compounds in the vegetable kingdom 
—addressed themselves to the chemical aspect of sorghum poison, and that accord- 
ingly it might be highly expedient to ascertain if the facts that they have brought 
to light are in harmony with what has been observed regarding the attendant circum- 
stances, both physiological and pathological, connected with the pronounced action of 
the plant here. This opinion is also that of the Government Veterinarian, Mr. W. 
©. Quinnell, at whose suggestion the reported discovery of prussic acid in sorghum 
was previously brought under your notice by me. 
I have, the honour to be, &c., 
HENRY TRYON, 
Vegetable Pathologist and Entomologist. 
The Under Secretary, Department of Agriculture. 
“QYANOGENESIS IN PLANTS. PART II.—THE GREAT MILLET, SORGHUM 
VULGARE,”* 
By Wynpuam R. Dunstan, M.A., F.R.S., Director of the Scientific Department of the 
Imperial Institute, and T. A. Henry, D.Sc., Lond. Received 24th April. Read May, 1902. 
(Abstract. ) } 
The authors have investigated the nature of the poison contained in the young plants of 
Sorghum vulgare, the Great Millet or Guinea Corn (the Juar of India or Dhurra shirshabi of 
Egypt). This plant is cultivated in tropical countries for the sake of theseed, which is important 
asa food grain. The young plants have proved fatal to animals, especially in Egypt, where the 
attention of the authors was directed to the subject by Mr. EK. A. Floyer, of Cairo, who has 
kindly provided the material required for the investigation. ; 
The authors show that the young plant, but not the seeds or old plants, when crushed with 
water, furnishes prussic acid (about 0:2 per cent. of the dried plant). The acid is not present in 
the free state, nor is it produced by acting on the plant with boiling water or with alcohol. The 
production of the poison is due to the action of a hydrolytic enzyme, apparently identical with 
the emulsin of bitter almonds on a cyanogenetic glucoside, which has been named ‘‘dhurrin,’ 
from the Arabic name for the plant ‘‘dhurra.” This glucoside has been proved to be derived 
from parahydroxylmandelic nitrile by the association of the residue of one molecule of dextrose. 
Its formula is therefore C,,H,,0,N. } 
I Fo 
INS 
NYA 
Thurrin crystallises well, and is soluble in both water and alcohol. When hydrolised by 
ulsin or by dilute acids, it is converted into parahvdroxylbenzaldehyde, dextrose, and hydro- 
yanic acid, according to the equation C,,H,,0,N + H,O =C, O02 + C,H1.0, + HCN. 
When warmed with alkalis, dhurrin is resolved first into dhurrinic acid and ammonia. This 
acid subsequently undergoes further hydrolysis when warmed with dilute hydrochloric acid, 
being convertedinto parahydroxylmandelic acid and dextrose: (1)0,,H,,0,N +H.O=0©,,H,,0, 
+ NH&; ; (2) C,,H1,0. + Hoo = C,H,0, + C,01206. 
The identity of the parahydroxylmandelic acid was established by its synthesis from the 
cyanhydrin of parahydroxy-benzaldehyde. 
Dhurrin differs from the other known cyanogenetic glucosides, the amygdalin of bitter 
almonds and the lotusin found by the authors in. Lotus arabicus, in being derived from the dextrose 
and not from maltose. 
The authors point out the protective purpose served by the existence of the cyanogenetic 
glucoside in the young plant. 
The authors intend to fully investigate the several problems which are raised by the 
occurrence of cyanogenetic glucosides in plants. ; 
They are at present engaged in examining several other (plants which have furnished prussic 
acid, amongst them being :—Manihot utilissima, Linum usitatissimum, Lotus australis, and 
Phaseolus lunatus. : 
Rxtract. PROCEEDINGS OF THE Royat Soorrry, Vol. LXX., No. 461, pp. 153, 154, 19rH JunE, 
* The authors’ previous paper, entitled “The Naturejand Origin of the Poison of Lotus arabicus’ (Proceed- 
ings, vol. 67, 1900, p. 224; vol. 68, 1901, p. 374; and {Phil. Trans. B. vol. 194, p. 515), is to be regarded as Part I. 
of this series. 
