165 
that such failures occur in practice is somewhat unfavorable to the 
general adoption of this remedy. 
The various powders used are tobacco, sulphur, pyrethrum, snuff, 
and common road dust (the latter presumedly acting by closure of the 
spiracles), and of the other substances, tobacco or preparations includ- 
ing this material may probably be considered as most generally use- 
ful. 
Pyrethrum, if dusted in among the hairs so as to thoroughly reach 
the insects when first applied, is quite effective and may be used for 
fleas and lice, but probably would not affect the mites. 
Fumigation is a method which presents some advantages where it is 
practicable, because it can be used during winter, when washes are 
objectionable and is preferable to powders, because all of the individ- 
uals affecting an animal may be killed and thus entirely free it, whereas 
by the other method the survival of a few individuals may restock the 
animal. A simple plan of adopting this is to cover the animal with a 
blanket, leaving the eyes and nose exposed, but having the blanket reach 
the floor or ground and made as tight as possible at all points to pre- 
vent the escape of fumes. Puff tobacco smoke under this blanket by 
means of a bee-smoker. This plan first came to my notice as recom- 
mended by Mr. Charles Aldrich, who claims for it very effective work. 
I have also seen a description of a plan for fumigation of fowls which 
involves the same principles. Some years ago* I suggested the plan 
of using a tight stall, with an opening for the head, a canvas protection r 
so as to leave the head, eyes, and nose exposed and free; and some 
experiments with this method showed that fumes of either sulphur or 
tobacco are very effective in destroying lice, both the Pediculidas and 
Mallophagida?. The time of exposure to the fumes varied from twenty to 
twenty-five minutes in these experiments. The sulphur or tobacco were 
burned over an alcohol flame, but I should presume a preferable plan 
would be to place the substance in a tin or sheet-iron tube, closed at 
one end, with the open end projecting into the stall, and drive the fumes 
off by means of heat applied to the under surface. The common little 
lamp-stove could be used. The stall should be made as small as possible 
to accommodate the animal, in order that the fumes may be as dense as 
possible, and on this account the simple covering with a blanket is per- 
haps preferable, as it adjusts itself to the animal, but provision should 
be made for the free circulation of fumes on the parts of the animal where 
the blanket would press. 
Feeding of sulphur with salt is strongly recommended by some, and 
Prof. Weed, of Mississippi Station, gives it a strong indorsement as a 
result of experiments at that station directed especially against the 
cattle tick (Ixodes bovis Riley). 
Bulletin Iowa Ag. College, Dept. Entomology, 1SX4, p. 78. 
