56 



BULLETIN 737, U. S. DEPARTMENT OF AGRICULTURE. 



coming in contact with the skin. When the chemicals are handled 

 with care and all details of the method understood, however, there is 

 no special danger and the method has been used in insect control for 

 many years with few records of serious accidents. 



EFFECT OF HYDROCYANIC-ACID GAS ON THE QUALITY OF TOBACCO. 



Hydrocyanic-acid gas is slightly lighter than air and all traces 

 of the gas are quickly removed from the tobacco by thorough airing. 



In order to determine whether or not any deposition of cyanogen 

 in the cigars occurs as a result of the cyanid treatment different lots 

 of freshly made cigars were fumigated at Key West, Fla., in 1912, 

 and sent to the Bureau of Chemistry, United States Department of 

 Agriculture, for examination. A list of the different lots of cigars 

 sent is shown in Table VIII. 



Table VIII. — Effect of hydrocyanic-acid gas on quality of cigars. Fumigation 



tests at Key West, Fla. 



Date fumigated. 



Exposure. 



1912. 



Apr. 20 



May 4 



May 10 



May 29 



June 8 



June 14 



June 18 



Not fumigated. (Used as check on treated lots.) 



Hours. 



24 

 24 

 48 

 24 

 36 

 24 

 24 



All lots of cigars were exposed to the air for a short time after 

 fumigation, and then sealed. As the amount of potassium cyanid 

 used was greater than is ordinarily employed in fumigation, the test 

 was a severe one. The cigars were received by the Bureau of Chem- 

 istry on July 8. The following report was received on November 12, 

 1912, from Mr. R. E. Doolittle, acting chief of the Bureau of Chem- 

 istry: "We have made a careful examination of the eight samples 

 of cigars submitted by you on July 8 last, and we are unable to detect 

 the slightest trace of hydrocyanic acid in any of the samples." 



Samples of cigars fumigated bj r the cyanid process and untreated 

 cigars of the same brand were submitted to a number of expert 

 cigar men at Key West, Fla., in order to ascertain if fumigation in 

 any way affected the flavor or quality of the cigars. All reported 

 that no difference between the treated and untreated cigars was ap- 

 parent, the uniformity of burn, capacity for retaining a light, and 

 color of ash appearing normal. 



