G. H. F. Nuttall 
103 
long hair may pick up lice, the insects soon reaching the root of the hair 
and finding refuge near the scalp. The greater activity of capitis at 
a temperature of 17-18° C., as compared to corporis, is clearly demon¬ 
strated; the latter only attains a full measure of activity at a higher 
temperature approximating to that close to the human body. At 
30° C., corporis is about as active as capitis at ca. 18° C.; it - is torpid at 
lower temperatures. 
Lice on hair climb as rapidly upwards as they do horizontally; they 
climb downward more slowly. Capitis climbs a single hair about as 
rapidly as it does two parallel hairs, whereas corporis climbs more rapidly 
along two parallel hairs. In short, these climbing records demonstrate 
a biological difference between the two races of P. humanus. 
DISSEMINATION OF LICE BY THE WIND. 
Under favourable circumstances lice ( corporis ) may be distributed 
by the wind. Schilling (1916, p. 1176), who records the first observation 
of the kind, states that Turkish officers had previously insisted that lice 
were carried through the air; some officers even supposing that the 
insects flew. Schilling reports that when examining Turkish soldiers 
in a valley in the Taurus, the soldiers stripped to the waist at a distance 
of 50-100 metres, and then walked up to be examined by a physician, 
behind whom stood a Commission of officers and engineers. The wind, 
of medium velocity, blew towards the Commission from the spot where 
the men undressed. Only the physician actually touched the men. 
After a short time, an officer observed a louse on his hand, a second 
officer found one on his coat, a third found one on his sleeve. After 
two hours, five out of six members of the Commission had captured 
1-4 lice apiece, all of them occurring upon the outer garments or hands. 
The captured lice were about 2 mm. long and filled with fresh blood, 
so that they had undoubtedly been wafted over from the men, being 
carried far because of their small size. Subsequently thrice as many men 
were similarly examined, the wind being stronger, but blowing across 
the path*pursued by the soldiers in approaching the Commission; on 
this occasion no lice were captured on members of the Commission. 
Still later, ten examinations of men on a large scale were made on a 
windless day and these also gave negative results. Schilling dwells 
on the importance of this observation in relation to the possible con¬ 
veyance of typhus and relapsing fever by lice carried from a distance. 
Schaefer (1916, p. 1507), moreover, states that he had occasion to examine 
