Gf. H. F. Nuttall 
511 
Itesults 
Eef. Insecticide tested 
No. (vapour and contact) 
Time when flannel treated before lice put on it 
1 hr 
20—24 hrs 
44—48 hrs 
68—72 hrs 
94 hrs 
Exposure 
4 hrs 
4 hrs 
6 hrs 
41 hrs 
308 
Veratrine, £ % in vaseline 
± 12/19 dead 
rest feeble 
± 9/19 dead 
rest feeble 
20/20 feeble 
1 dead, 17 
feeble, 1 active 
Exposure 5 hrs 
4 hrs 
5 hrs 
5 hrs 
309 
Harrison’s pomade ± 19/21 dead 
± 2/20 dead 
± 5/21 dead 
± 2/23 dead 
rest feeble 
rest feeble 
but 4 active 
but 7 active 
310 
Veratrine, \ % in vaseline ± 5/19 dead 
± 3/22 dead 
± 3/22 dead 
± 4/20 dead 
— 
rest feeble 
rest feeble 
but 1 active 
but 5 active 
In Experiments 311-328 (Vapour and Contact or vapour alone) 
small quantities of the preparation (0-2-0-26 g.) were placed in a thin 
cotton pocket (15 mm. square) which was stitched to a slip of flannel, 
the lice were confined within an area ca. 47 mm. square by chiffon 
stitched to the flannel so that the pocket containing the insecticide 
occupied a central position beneath the chiffon cover. The confined lice 
could range away to a distance of ca. 16 mm. from the insecticide pocket. 
The latter was charged with insecticide powder or paste; as some pastes 
spread, the lice in such cases came in contact with them. Only the most 
efficient vapours and widely spreading contact remedies killed all the 
lice. The method was found to be much more delicate than that used 
in Expts 286-310, and the action of the insecticide was slower. The 
flannel was pinned to the experimenter’s shirt etc. as described for Expts 
286-310. 
Eef. 
No. 
Insecticide tested 
Lice exposed 4 hours 
311 
312 
313 
Naphthaline, pure, commercial, 
finely powdered 
Ditto, crude, unwhizzed* 
Ditto, crude and soft soap 
20 dead 
65 „ 
55 „ 
26 feeble 
14 „ 
23 „ 
45 active 
12 „ 
13 
Eef. 
No. 
Insecticide tested 
Lice exposed 4—5 hours 
314 
315 
316 
N.C.I. powder 
Naphthaline, commercial, finely 
powdered 
Ditto, second sample 
63 (51 %) dead 
51(43%) „ 
61 (50 %} „ 
44 feeble 
27 „ 
29 „ 
17 active 
41 „ 
32 „ 
* For explanation see footnote p. 537. 
9 
