Feb. 17, I9I9 Cy anagenesis in Andropogon sorghum ijy 



dryness, freshly prepared ferrous sulphate was added and acidified with 

 30 per cent nitric acid as directed by Viehoever and Johns (9). Instead 

 of filtering the Prussian-blue precipitate into a Gooch crucible, as was 

 done by Knight (5), it was filtered in the ordinary way and washed 

 thoroughly with dilute nitric acid and then with water. The precipitate 

 and filter paper were then placed in a flat-form platinum dish and heated 

 slowly to dryness in an electric muffle furnace, and then heated strongly to 

 burn the precipitate and oxidize the iron. The dish containing the resi- 

 due, consisting of the ash of the filter paper and the ferric oxid, was 

 weighed. From the weight of the ferric oxid the amount of hydrocyanic 

 acid was calculated, and from this the percentage of hydrocyanic acid in 

 the dry sorghum. The percentage of moisture in the different samples 

 of sorghum was found by drying at 105° C. 



No effort was made to determine whether or not this method would 

 give accurate results, but it was thought that the results would be as 

 accurate as those obtained in using Knight's method (5); the colori- 

 metric method of Viehoever and Johns (9) and of Francis and Con- 

 nell {4) could not be used, since a colorimeter was not available. More- 

 over, it was thought that this method would give results sufficiently 

 accurate for comparative purposes. 



In order to determine whether or not a part of the hydrocyanic acid 

 was lost in the drying, sample 3 was cut and digested as described above, 

 and then some of it was allowed to dry in the laboratory for 2X days 

 and was then placed on top of a Freas oven overnight. The temperature 

 on top of this oven was 33° C. A part of this sample was used for the 

 determination of hydrocyanic acid and another for the determination 

 of the water still present. 



In order to determine the effect of the rate of drying on the loss of 

 hydrocyanic acid, if any, another part of sample 3 was dried at 50° C. 

 within 24 hours. The results obtained here are given in Table I under 

 experiments i, 2, and 3. 



In order to determine the effect of the presence of glucose and maltose 

 on the liberation of the hydrocyanic acid, portions of sample 2 were 

 digested in a solution containing i per cent of dextrose and i per cent of 

 maltose. The results of two trials here are given in Table I under 

 experiment 5. 



To determine whether or not a part of the hydrocyanic acid existed 

 in the form of nonglucosidic acid, as has been claimed by Willaman (10), 

 portions of samples 2 and 3 were digested, and 200 cc. distilled off. Then 

 50 cc. of 10 per cent sulphuric acid were added to the digestion mixture, 

 which had a volume of about 800 cc, and another 100 cc. was distilled. 

 This last distillate was evaporated, and tests were made for hydrocyanic 

 acid, with negative results, as indicated in Table I under experiment 6. 



It has been pointed out by Auld (z) that with most feedstuffs digestive 

 conditions would be unfavorable for the action of the enzym on the 



