Oot. is, 1925 Chloropicrin as a Fumigant for Cereal Products 749 
used by Moore and in this present work. Furthermore, in one case 
he merely poured the chloropicrin over sacks of grain, after which 
the pile was covered with a tarpaulin. It is not surprising that the 
small amount of chloropicrin used was soon reduced by diffusion 
to the point where it failed to kill. 
In the course of these experiments, a room 80 by 18 feet was 
fumigated to kill the Indian-meal moth, Plodia interpundella Huebn. 
The walls of the room were cracked, and the larvae had gone into the 
cracks to pupate. All of the walls and ceiling and floor were sprayed 
with chloropicrin at the rate of about 32 gms. per cubic meter for the 
volume of the room. The adult moths dropped to the floor as soon 
as they were touched by the spray, and the larvae and pupae were 
subjected to an atmosphere saturated with chloropicrin at the start. 
All the insects were killed. The room was aired by means of an 
electric fan placed in the only window. 
In another case, the empty grain bin of an elevator which was 
infested with the granary weevil was treated in the same way. Here 
again the insects were in cracks in the wall. This'method subjected 
them all to an atmosphere which was practically saturated with 
chloropicrin at the start, which resulted in their death in a very short 
time. At the same time the concentration was high enough in all 
parts of the bin to kill any insects which failed to come into contact 
with the liquid. 
When infested grain was placed on the floor of an open box and 
sprayed with chloropicrin, the insects actually hit by the spray were 
killed while others 2 feet above the floor survived. 
From these experiments it seems evident that, by virtue of its 
penetration property, chloropicrin is able at the same time to pene¬ 
trate materials which contain insects, and to escape through the 
walls of the fumigation chamber so rapidly that its concentration 
may soon fall below the lethal point. When the material is applied 
as a spray, the surface of the chloropicrin is so increased that it 
volatilizes very quickly, thus building up a high concentration in 
the atmosphere before it begins to escape. Also, the spray can be 
directed to the infested areas, thus giving the insects a saturated 
atmosphere at the start. 
EFFECTS OF CHLOROPICRIN ON FUMIGATED CEREALS 
In the use of any material as a fumigant for cereals, not only are 
its toxic effects on the infesting organism and its freedom from fire 
hazard of importance, but worthy of equal consideration are its 
effects, physical and chemical, on the material fumigated. When 
wheat or flour which is to be used in making bread is the particular 
cereal fumigated, these effects may be differentiated into at least 
two phases. The first of these concerns the effects of the fumigant 
on the colloidal nature of the proteins of the flour as indicated by a 
physico-chemical study of such proteins. The second has to do with 
the effects on yeast activity, in particular on the rate of production 
of carbon-dioxide gas by the yeast organism. In this paper the 
use of chloropicrin as a fumigant will be considered from the several 
angles indicated. 
