492 
Combating Lousiness 
These experiments were therefore repeated under the following 
conditions at ca. 15° C.: 
Exp. I. (Control to that of Teske.) Two glass dishes were placed side by side 
and a piece of cloth of the same size and fabric was placed in the centre of each dish; 
50 hungry lice were transferred to each piece of cloth. About 0-5 c.c. of oil of anise 
was dropped on one of the pieces of cloth. After 2| hrs 31 lice had abandoned the 
anise-cloth and 30 had left the control cloth. The experiment therefore did not prove 
that anise repelled lice in the slightest degree. 
Exp. II. (Control to that of Sergent and Foley.) A piece of cloth was cut in two 
parts of equal size, the pieces being placed side by side, 4 cm. apart, in a glass dish. 
50 lice were placed in a mass between the two pieces of cloth upon one of which was 
dropped the repellant to be tested. 
Oil of Eucalyptus, tested in the light. After J hr there were found 3 lice on the 
eucalyptus cloth, 44 on the clean cloth and 3 scattered in the dish. After 2] hrs 
there were 11 lice on the eucalyptus cloth, 15 on the clean cloth and 24 scattered in 
the dish on the side furthest from the eucalyptus. 
Tested in the dark. After 1J- hrs there were 16 lice on the eucalyptus cloth, 
15 on the clean cloth and 19 scattered in the dish. 
The amount of oil used was small (1 drop). At first the result was striking, but 
later, owing to some oil having evaporated, the effect ceased to be evident as shown 
in the experiment carried out in the dark. The experiment was now repeated in 
the dark with 
Oil of Anise. Result after If hrs: 3 lice on anise-cloth, 5 on clean cloth, 42 scattered 
in the dish on the side furthest removed from the anise. 
Oil of Cloves. Result after If hrs: 0 lice on clove-clotb, 47 on clean cloth, 
3 scattered. 
These experiments therefore demonstrate conclusively that the three essential 
oils tested in small quantity exert a marked repellant effect on lice through their 
vapour. 
Exp. III. (Control to that of Jeanneret-Minkine.) Carried out as described by 
the author, but omitting the stove and placing the cloths in a glass dish. 50 lice 
tested. After 2). hrs only 8 of the lice had abandoned the cloth. Therefore there 
was no evidence of repulsion. 
Note. In the section on biology (p. 180) it is stated that there is no evidence 
of lice possessing an olfactory sense. The foregoing experiments do not establish 
that the insects possess such a sense for the repulsion may be due to other causes. 
In this connection may be cited an experiment of R. Crocker’s (quoted by Dubreuilh 
and Beille, 1895, p. 121) wherein 4 students were placed about a table on which a 
louse was placed. Crocker states that whatever position the louse and men took up, 
the insect always walked toward the same man. As nothing is stated with regard 
to the possible effects of light and the colour of the men’s clothes upon this choice 
on the part of the insect I repeated the experiment as follows: 
Exp. IV. 100 hungry lice were dropped in the centre of a large piece of brown 
cardboard on the rough surface of which was drawn a circle. The card was placed on 
a support about breast high in a room moderately lit by an electric bulb hanging high 
and immediately above the card. Four persons clothed approximately in the same 
