May 15, 1916 



Hydrocyanic-acid Content of Sorghum 



263 



The differences noted are within the limits of accuracy of sampling and 

 analyzing; hence, this method of preservation can safely be used on 

 sorghum plants at least through the stages of maturity represented in 

 these experiments. 



About 50 gm. of the sample, after thorough mixing and fining with a 

 knife, were used to determine the percentage of dry matter. For the 

 determination of the hydrocyanic-acid content, from 50 to 70 gm. were 

 ground in a food chopper, placed in an 800 c. c. Kjeldahl flask, together 

 with 250 c. c. of 5 per cent tartaric acid, and distilled slowly into 10 c. c. 

 of 2 per cent sodium hydroxid until the distillate was nearly 100 c. c. 

 This completely hydrolizes the dhurrin and carries the hydrocyanic acid 

 over into the' alkaline distillate. The latter was made to 100 c. c. and 

 aliquots used for the determination of hydrocyanic acid according to the 

 method of Viehoefer and Johns (9) . This method was found to be easier 

 and more accurate than the thiocyanate method used in 1914. 



The complete analytical results appear in Table II. The figures for 

 the amount of hydrocyanic acid in the whole plant were computed from 

 the relative proportion of leaves and stalks in each sample. 



Table II. — Hydrocyanic-acid content of sorghum from the various experimental plots 

 [The percentage of hydrocyanic acid is reported on a dry-matter basis] 



