ABSORPTION OF HYDROCYANIC ACID BY FOODS 3 
by aeration from the open hatches for four hours. Hydrocyanic 
acid was found in almost all of the fumigated foodstuffs, the quantity 
increasing with the water content, in the following order: Water; 
banana peel ; banana fruit ; oranges ; edible oil : shell eggs ; egg albumen ; 
bread; tea; flour; wheat, oats, and peanuts; beans and corn. The 
last two groups contained very little fumigant. Apparently Bonjean 
did not determine the exact quantity of hydrocyanic acid retained. 
Hydrocyanic -acid, he stated, was not held in foods in quantities 
sufficient to be toxic. 
Among the advantages of using hydrocyanic acid gas enumerated 
in a preliminary report of the board appointed by the Surgeon General 
of the United States Public Health Service to investigate the fumiga- 
tion of ships (1) it is stated that this gas does not affect foodstuffs. 
Stock and Monier- Williams (8) made the following statement : 
Experiments carried out during an experimental fumigation at Tilbury Docks 
showed that foodstuffs of the most varied kind, meat, butter, flour, &c, did not 
absorb more than traces of hydrogen cyanide under the conditions of the experi- 
ment. It would seem probable that even if the gas were absorbed in small 
amounts, it would be rapidly evolved or oxidised on subsequent exposure to air 
or on cooking. Nevertheless it has been the practice to remove moist or liquid 
foodstuffs such as meat, milk, &c, before fumigation, and either to empty or to 
seal up fresh-water tanks. 
The literature contains references also to the use of a mixture 
which is said to contain about 90 per cent of cyanocarbonic ester and 
10 per cent of chlorocarbonic ester. The cyanocarbonic ester is said 
to break down immediately in contact with moisture, to form hydro- 
cyanic acid. (The chlorocarbonic ester is used as an indicator on 
account of its lacrymatory power.) Fumigation with this product 
thus corresponds to some extent to fumigation with hydrocyanic acid. 
Jansen, Schut, and Wagenaar (o) fumigated food products in a ship 
with this mixture and then calculated the quantity of hydrocyanic 
acid absorbed to the original material. Their results are of the same 
order as those found when hydrocyanic acid is used as the fumigant, 
making allowance for the fact that their fumigant contained only 
about 24 per cent of cyanogen. 
EXPERIMENTAL WORK 
DREED FRUITS 
Dried fruit does not cost as much to ship and is not as subject to 
decay as fresh fruit. It is, however, subject to attack by insects. 
The problem of insect control becomes particularly serious when it is 
necessary to carry dried fruit over from one year to another. Because 
of the high cost of the present practice of keeping dried fruit in cold 
storage, Dr. L. C. Corbett of the Bureau of Plant Industry pointed 
out the value to the industry of fumigation with hydrocyanic acid 
to prevent insect injury, if it could be done without injuring the fruit 
for consumption. Experiments were therefore undertaken to find 
how much gas these products would retain after fumigation and how 
long they would hold it. 
Dried fruits were bought in the open market. In most cases com- 
mercial packages were fumigated without being opened until the 
fumigation was finished. In all cases, small quantities were fumigated 
without any protection from the gas. 
The fumigations were carried out at atmospheric pressure by the 
"pot " method, using sodium cyanide, sulphuric acid, and water, in the 
