138 Journal of Agricultural Research voi. xxii. No. 3 



Table XVIII. — Effect of different treatments on liberation of hydrocyanic acid in sorgo 



Sample 



No. 



Treatment. 



HCN. 



Digested in water and distilled 



Digested in water and distilled 



Digested in water and distilled from Njo.^ H2SO4. . . 

 Digested in water and distilled from NIo.i H2SO4. . . 

 Digested in water and distilled from NI0.02 H2SO4. . 



Mgni. 



72 

 80 

 64 

 72 

 89 



EFFECT OF HYDROCYANIC ACID FROM GREEN SORGO ON A HORSE 



Ten-pound portions of green sorgo, testing the amount of hydrocyanic 

 acid given in Table XVIII, were fed to a horse. No effect on respiration, 

 pulse, or temperature could be observed by Dr. H. F. Lienhardt, of the 

 Veterinary Division, who made the observations. Data presented in 

 this paper show that such a degree of acidity as is found in the stomach 

 of a horse would prevent liberation of hydrocyanic acid from the green 

 material. Feeding wilted sorgo was not tried. 



SUMMARY 



(i) In this paper are presented data givmg the results of tests made 

 on Sudan grass for hydrocyanic acid during the summer and early fall of 

 1920. 



(2) The maximum amount of hydrocyanic acid was obtained by mac- 

 erating the material and digesting in water at room temperature for about 

 six hours or overnight. 



(3) Practically all the hydrocyanic acid was found in the leaves. In 

 well-developed stems none was found. 



(4) More hydrocyanic acid was found in younger plants than in those 

 more mature. This is due mostly to stem development. If leaves only 

 are used the dififerences are small, except when the plants approach 

 maturity. More was found in the summer than in the fall. 



(5) Hydrocyanic acid does not exist as free HCN in the growing plant. 

 It begins to be liberated as soon as the plant is macerated or undergoes 

 wilting. 



(6) Liberation of hydrocyanic acid is intimately associated with enzym 

 action. If this enzym action is inhibited by addition of hot water or 

 acids, no hydrocyanic acid will be liberated. Hydrocyanic acid was 

 obtained from wilted grass when hot water was added, because during 

 the wilting process hydrocyanic acid was set free. 



(7) Hydrocyanic acid can not be set free from the green material by 

 acids. 



(8) The action of strong alkali is similar to that of acids. 



(9) Most hydrocyanic acid is present when the plant is in a vigorous 

 growing condition. 



(10) Sudan grass contains less hydrocyanic acid than sorgo or kafir. 



