390 Haematopinun asini 
Attempts to feed the female lice on animals other than the horse were likewise 
unsuccessful 1 . 
Eventually cages were made by covering the bottom of pill boxes (ca. 
1| inches diameter) with gauze and the top with linen; these boxes were 
filled loosely with horse-hair and placed under a felt pad (ca. 9 inches x 3 inches 
x | inch). Three holes, to fit the boxes, were cut in the centre of the felt to 
a little less than the depth of the box and in the centre of each of these de¬ 
pressions a hole (J inch) was cut to ensure ventilation. The pad with its three 
cages was fastened to the horse’s side by a kind of broad surcingle made of 
open mesh (J inch) string netting. About 50 $$ and 12 dd were placed in each 
box. This device answered our purpose, but many lice failed to feed through 
the gauze and consequently the number of eggs obtained was limited. 
( b) Incubation at 100° F. (dry). The first trials were made by simply 
placing the eggs in an incubator at 100° F. Of ten batches of about a dozen 
each, not a single egg hatched in a month, none showed signs of development 
—they had simply dried up. 
To prevent this dessication the boxes were placed on a wire tray supported 
over water so as to keep the atmosphere always saturated with moisture. 
Under these conditions a batch of ten eggs all hatched on the sixteenth day. 
(c) Incubation at 70°-80° and 100° F. (damp). The next trial was made at 
a lower temperature in an old incubator with a fluctuating temperature of 
from 70° F. at night to 80° F. by day. The eggs were collected every 24 hours 
and each batch divided into two equal lots, the first lot being placed in the 
above incubator with a dish of water, and the second incubated simultaneously 
at 100° F. 
The following is the result. 
Ph 
o 
8 
o' 
o 
100° F. 
Eggs hatched on day 15 (evening) 
— 
14 1 
5 j 99 16 ... ••• 
— 
91 > Total hatched 112 
„ „ 17 (morning) 
— 
V ] 
Eggs failed to hatch (2 months) 
117 
2 } Total failed 119 
Of the eggs incubated at 70°-80° F. 94 developed moulds, 12 became discoloured and soft, 
and 11, which after three months showed no change, were found on being opened to contain a 
viscid opalescent fluid. 
(d) Incubation at 85°-100° and 100° F. Two experiments were made, 
each in a humid atmosphere and with a temperature fluctuating between 
85° F. and 100° F. The first was made in the incubator mentioned in the last 
experiment, 36 eggs in five lots being used, and five lots of two eggs each as 
controls. The second was made by placing the eggs in a bag and incubating 
by a similar method to that used in the preliminary experiment, 58 eggs in 
1 Of seven lice kept on the arm of one of the writers, only two bit and succeeded in filling 
themselves with blood, but they died next day whilst the remainder lived three days longer. Out 
of some dozens of lice tested at various times, only three have been induced to feed. 
