GL17 

 (leaf 2) 



result from eating the plant in hay. In 1933 Beath et al. 4 found 

 that the poison resides chiefly in the leaves; that the drying of the 

 plant results in the loss of varying amounts of HCN, but that this 

 is partly counterbalanced by the tact that the acid is more readily 

 and completely released than in the green plant ; that frosted, wilted, 

 and stunted plants are less toxic than normal growth, and that, for 

 some unknown reason, air-dried samples cured in hay differ mate- 

 rially in their retention of toxicity. 



Beath et al. 4 regard this plant as the most rapidly acting poisonous 

 species found on the western stock ranges. Hydrocyanic acid is the 

 active poisonous principle. To produce poisoning, the toxic dose 

 must be eaten in a short period of time. The sickness comes on very 

 quickly, lasts a comparatively short time, and in cases of recovery 

 seems to have no permanent effect. 1 The usual symptoms of poison- 

 ing by seaside arrowgrass are typical of hydrocyanic acid poisoning 

 in general, i. e., brief stimulation followed by depression and paraly- 

 sis. Colic often occurs accompanied by stupor, difficult breathing, 

 and frequent convulsions. Death results directly from respiratory 

 paralysis, and frequently the heart continues to beat after breathing 

 has ceased. 5 



Remedies for cyanide poisoning are as yet in the experimental 

 stages. Recent experiments have shown that injections of a combi- 

 nation of sodium nitrite and sodium thiosulphate are effective in 

 the treatment of cattle and sheep poisoned by arrowgrass. 6 How- 

 ever, death in most cases occurs so quickly that there is little oppor- 

 tunity to apply remedial measures. Certain feeds, such as alfalfa 

 hay and linseed cake, seem to retard the production of hydrocyanic 

 acid in the animals' stomachs and may prevent poisoning. The best 

 way to prevent losses is not to pasture livestock on meadows con- 

 taining an abundance of the plant and to refrain from cutting arrow- 

 grass for hay. 



Seaside arrowgrass is apparently poisonous throughout its entire 

 growth period. Differences of opinion among stockmen about the 

 poisonous properties of this species are no doubt largely attributable 

 to the latent factors which increase or decrease the potential amount 

 of hydrocyanic acid in the various plants. Hydrocyanic acid does 

 not actually occur in any appreciable quantity in healthy growing 

 plants, but two chemical substances are present, which, though not 

 poisonous individually, combine to form hydrocyanic acid. 6 The 

 amount of potential hydrocyanic acid in the various plants capable 

 of producing hydrocyanic acid poisoning varies with the stage of 

 growth and climatic and soil conditions; the damaging effects of 

 drought, frost, trampling, or mowing tend to stimulate the formation 

 of the poison in the plants. 6 



4 Beath, O. A., Draize, J. H., and Eppson, H. F. ARROW GRASS CHEMICAL AND PHYSIO- 

 LOGICAL CONSIDERATIONS. Wyo. Agr. Expt. Sta. Bull. 193, 36 pp., lllus. 1933. 



CoUCh, J. F. POISONING OF LIVESTOCK BY PLANTS THAT PRODUCE HYDROCYANIC ACID 



U. S. Dept. Agr. Leaflet 88, 4 pp. 1932. 



6 Bunyea, H., Couch, J. F., and Clawson, A. B. THE NITRITE-THIOSULPHATE COMBINA- 

 TION AS A REMEDY FOE CYANIDE POISONING IN SHEEP. Jour. Wash. Acad. Sci. 24(12) : 

 528 532. 1934. 



