G. H. F. Nuttall 
507 
its vapour only penetrated into the interior of the tube. The lice were 
exposed for periods up to 24 hrs. Unless all of the insects were killed 
I have entered them as “survived” in the table. Swellengrebel believes 
that no vapour is sufficiently insecticidal for practical purposes. 
Bacot (ix. 1916, pp. 447-450), in his experiments, used small wire 
framed cells covered by gauze and tied in a row close together. The 
cells were worn against the body. Known quantities of insecticide 
were placed on lint in some cells (contact cells) whilst others contained 
no insecticide (control cells). The cells were worn for 8-12 hrs a day 
and the results recorded. The lice in the control cells were subject to 
the vapour emanating from the contact cells (the results with the contact 
cells are cited on p. 498 under contact experiments). 
Ref. 
No. 
Insecticide tested 
(vapour) 
Experimental conditions 
250 
Acetic acid, strong 
See note above (Swellengrebel), 
10 c.e. acid used 
251 
„ „ 50 % 
ditto 
252 
Ammonia, 25 % 
See note 
253 
Anisol 
ditto, 10 c.c. used 
254 
Cresol 
ditto 
255 
Cresylic acid 
See note above (Bacot) 
256 
Cytisine* 
ditto 
257 
Globol 
See note (Swellengrebel), used 
17 g. 
258 
H 2 S aqueous soi. 
See note, solution renewed every 
11 hrs 
259 
Iodoform* 
See note 
260 
Lausofan 
See note, 51- g. used 
261 
No particulars 
262 
263 
Naphthaline 
See note (amount not stated) 
264 
ditto 
265 
55 
55 
266 
Naphthaline oint- 
Lice in box, no particulars 
ment 
Oils (essential) 
See note, amount not stated 
267 
,, anise 
268 
,, bergamot 
See note, 15 c.c. used 
269 
„ turpentine 
See note, amount not stated 
270 
Pyre thrum 
Dusted on clothes, lice in box, on 
person 
271 
Texan 
2 sachets on back and breast as 
recommended by Gross 
272 
Vermijelli 
See note (Bacot) 
Result 
Au¬ 
thority 
Lice killed in 4£ hrs 
Lice survived 24 hrs exposure 
n u 10 jj >> 
IS 
55 55 55 
JJ 55 ^ 55 55 
Lice, mostly survived 2x10 
hrs exposure 
Lice (10 %) survived 2 x 10 
hrs exposure 
Lice survived 13 hrs exposure 
55 55 
55 
Lice (10%) survived 2x10 
hrs exposure 
Lice survived 24 hrs exposure 
Lice killed by 3—5 hrs exposure 
Nits killed by 6 hrs exposure 
Lice survived 6 hrs exposure 
Lice mostly survived 10 hrs 
exposure 
Lice mostly survived 2x10 
hrs exposure 
Lice only killed after “a long 
time” 
Lice survived 6 hrs exposure 
55 55 55 
55 55 55 
Even the best powder almost 
useless 
Lice survived 6 hrs exposure 
Lice mostly survived 9 hrs ex¬ 
posure 
S. 
S. 
S. 
S. 
S. 
B. 
B. 
S. 
B 
W. 
w. 
s. 
B. 
B. 
H. 
S. 
S. 
s. 
H. 
S. 
B. 
* Too costly for practical use. 
Parasitology x 
33 
