Oct. 15, I93I Hydrocyanic Acid in Sudan Grass 129 



The results show that more hydrocyanic acid is found in the whole 

 plant in the earlier stages of growth and less as the season advances. 

 The difference is perhaps due to the large proportion of stems in the 

 latter part of the season, since if leaves only are compared there is very 

 little difference except where they are from mature plants. This indi- 

 cates that most of the hydrocyanic acid is obtained from those parts of 

 the plants where the vegetative activity is most pronounced. This 

 agrees with the results obtained by Menaul and Dowell ^ at the Okla- 

 homa Agricultural Experiment Station. These observations support the 

 theory that hydrocyanic acid is an intermediate product between the 

 nitrates and the amino acids. ^ 



DISAPPEARANCE FROM MACERATED MATERIAL 

 As soon as the grass is macerated the hydrocyanic acid begins to pass 

 off. This was demonstrated several times by suspending small pieces 

 of sodium-picrate paper above some macerated grass in stoppered flasks. 

 The paper very soon assumed a brown color. The quantitative deter- 

 minations given in Table VI were made on samples macerated July 10 

 and treated as indicated. 



Table VI. — Disappearance of hydrocyanic acid in macerated grass 



_ 



^X!'^ Treatment. | HCN. 



Digested in water two days 



Placed without added water in covered mason jar for two days then 

 small amount of water added and distilled 



Placed in flask two days so that the hydrocyanic acid could escape 

 only into the receiving flask, after which water was added and 

 distilled 



4 Left in open jar for two days, digested and distilled 



5 Repeat of 3 but kept in flask overnight only 



Mgm. 

 25 



26 

 Trace. 

 26 



DISAPPEARANCE FROM GRASS AFTER CUTTING 



In a previous paper ^ it was stated that tests made on partially wilted 

 grass may be worthless. In the experiments made at that time, the 

 amount of sulphuric acid added was not carefully enough controlled. It 

 will be shown in the following paragraphs that if acid is added beyond 

 certain limits no hj^drocyanic acid will be obtained from either green or 

 partially wilted grass. In each of the determinations given in Table 

 VII the grass was macerated after the treatment stated and then di- 

 gested in water overnight. 



1 Menaul, Paul, and DowEi,!,, C. T. cyanogenesis in sudan grass: a modification of the franos- 

 CONNELI, METHOD OF DETERMINING HYDROCYANIC ACID. In Jour. Agr. Research, v. i8, no. 8, p. 447-450. 

 1920. 



2 Ravenna, C, and Zamorani, M. ntjove ricerche sulla fxjnzione fisologica dell, acido ciani- 

 DRICO NEL SORGHUM VULGARE. In Atti R. Accad. Lincei, Rend. Cl. Sci. Fis., Mat. e Nat., v. 18, sem 

 2, no. 8, p. 283-287. 1909. Abstract in Chem. Abs., v. s, no. 6, p. 1113. 1911. 



' SWANSON, C. O. HYDROCYANIC ACID IN SUDAN GRASS AND ITS EFFECT ON CATTLE In Jour. Amer. 



Soc. Agron. , v. 13, no. i, p. 33-36. 1921. 



