EXTERNAL PARASITES 211 
birds to become dry before night. By the dipping method the cost 
for material is 58 cents per hundred birds. For material and labor 
both, it is 71 cents. 
Bishopp and Wood note that several other agents are effective in 
destroying lice, but are more expensive than so- 
dium fluorid. Flowers of sulphur applied with a 
dust can in an amount of about 6 pounds per hun- 
dred fowls is effective in about four days. Dip- 
ping fowls in a solution of 1 ounce of laundry soap 
to a gallon of water, repeated in ten days is ef- 
fective. 
Herrick strongly recommends the Cornell or 
Lowry dusting powder made as follows: Two and g 
one-half pounds of plaster of Paris is spread ina fic. 41. Mass of 
shallow pan or tray. One-fourth pint of crude body lois Pass 
carbolic acid is poured into a cup, and into this is — feather. Greatly 
poured three-fourths pint of gasoline. The mix- pao conn 
ture of acid and gasoline is poured over the plas- aoe 
ter of Paris and thoroughly mixed. It is then rubbed through a 
wire window screen on-a piece of paper and allowed to stand for 
from one and one-half to two hours or until thoroughly dry. It 
must not be placed near a flame or any heat. The powder should be 
kept in a closed can or jar, where it will retain its strength for a long 
time. The powder is applied by means of 
an ordinary sifter or with the fingers. It is 
worked in among the feathers about the vent, 
in the fluff, and under the wings. Two and 
perhaps three applications should be made. A 
small pinch of the powder is sufficient for a 
fowl. The rooster should receive especial care 
in being kept free from lice, as he is an im- 
portant factor in spreading the parasites. 
The expense of this treatment including la- 
bor should not exceed 32 cents per hundred 
fowls. 
Fie. 42. Largehen louse. The effectiveness of this method of dusting 
(Goniocotes abdomi- _, : b 
nalis): Male, top birds for lice has been called into question by 
eae a eee en- several observers. 
: Lamson and Manter recommend the appli- 
cation of a dilution of either mercurial ointment or blue ointment. 
Mercurial ointment was considered cheaper when judged on the basis 
