﻿4 BULLETIN 1149, U. S. DEPARTMENT OF AGRICULTURE. 



Investigators in the United States Public Health Service (1) fumi- 

 gated bread and milk with hydrocyanic acid and then fed them to 

 white mice. They found that ''"when exposed to the cyanide gas in 

 the concentration usually advised for fumigating tight compart- 

 ments" they "did not absorb or adsorb sufficient cyanide to cause 

 symptoms, when fed to white mice." With double the amount of 

 hydrocyanic acid, "prolonged" exposure, and no aeration after 

 fumigation, death of the mice resulted, but "after one or two hours 

 exposure of the food to the air no symptoms were produced." They 

 summarize, "The conclusion from these experiments is that the pos- 

 sibility of food poisoning occurring from food materials exposed to 

 cyanide gas is extremely, remote." 



Lubsen, Saltet, and Wolff (15) state that hydrocyanic acid can be 

 used for the destruction of insects in flour and other foodstuffs, since 

 it does not affect foods, except milk and other liquids. 



Marchadier, Goujon, and de Laroche (16) advise against the use of 

 hydrocyanic acid fumigation for flour. They recognize its value for 

 clothes and things of that type, but think that flour may hold enough 

 of the gas to cause injury to health. They found a hydrocyanic 

 acid content of 82 parts per million in one flour and say that the 

 foods prepared from it (cakes, sauces, etc.) still had the taste of 

 cherry laurel) even after cooking. They do not describe the treat- 

 ment which the flour had received. 



PURPOSE OF PRESENT INVESTIGATION. 



There are no analytical data on the quantity of hydrocyanic acid 

 absorbed under the usual conditions of fumigation, except those of 

 Guthrie and of Bail, who give some results on five products, but none 

 which indicate the rate of loss of hydrocyanic acid on aeration. 

 Schmidt worked with excessive concentrations of the fumigant. 



Experimental work was therefore undertaken in the United States 

 Department of Agriculture to find how much hydrocyanic acid is 

 absorbed under ordinary conditions of fumigation on a large number 

 of fruits, vegetables, and seeds, and at what rate it is given off when 

 the products are exposed to the air. 



EXPERIMENTAL WORK. 



FRUITS AND VEGETABLES. 



Fruits and vegetables were bought in season in the open market 

 and in a condition as nearly perfect as possible. They were divided 

 into three lots. 



One lot was analyzed without being fumigated, to guard against 

 reporting as absorbed hydrocyanic acid any which mignt be present 

 in the fruit naturally. 



The second lot was fumigated at normal atmospheric pressure 

 (NAP) by the "pot" method. The fumigant in this method was 

 prepared by adding sodium cyanide to diluted sulphuric acid in the 

 proportion of 1:1^:2. That is, for every avoirdupois ounce of sodium 

 cyanide \\ fluid ounces of sulphuric acid and 2 ounces of water 

 are used. 



The third lot was fumigated by a modification of the vacuum 

 method described by Sasscer and Hawkins (20). The fumigant in 

 this method was prepared from sodium cyanide, sulphuric acid, and 



