Gr. H. F. Nuttall 
111 
the skin for 6-7 hours by night. The boxes were carried in the clothes’ 
pockets by day. In some experiments the eggs were allowed to hatch 
at 31° C. in the thermostat. By using a fine quality of chiffon as a 
screen to the boxes, Bacot was able to deal effectively with larvae. In 
raising capitis, Bacot placed hair loosely in the boxes above described 
instead of folded bits of cloth. 
Relative advantages of the foregoing methods. 
For obtaining a true picture of the biology of corporis, my felt cell 
method is the best since it places the insects under natural conditions 
where they at all times have direct access to the skin for feeding; they 
are, moreover, provided with retreats similar, to those afforded by seams 
in clothing, and the climatic conditions are normal. The objection to 
the method lies in the necessity of bandaging and unbandaging the arm 
for inspection. 
Failing this, the next best is the wristlet method as used for my 
experiments with capitis. The chiffon screen on the top and bottom 
of the box prevents the condensation of moisture within that inevitably 
takes place where glass-bottomed boxes are used as in Bacot’s method. 
The pill-boxes can, moreover, be much more rapidly opened, cleaned 
and inspected, and, being shallow and the chiffon fine, a great deal of 
what is going on in the boxes can be seen through the chiffon with a 
hand-lens or binocular microscope without disturbing the inmates. It 
is a great safeguard against the escape of small larvae if the chiffon is 
impregnated and stiffened with a varnish like shellac. Successive 
batches of eggs, laid on hair grids, can be removed to other boxes that 
are carried in a bag about the neck prior to hatching. For examination, 
the boxes, when opened, are best placed in glass dishes. The lice stay 
upon the chiffon floor and hair grid, occasionally upon the chiffon lid, 
laying nearly all their eggs on hair. The method will work equally 
well with corporis. 
To lay their full quota of eggs per day lice must have unlimited 
opportunities of feeding. This is demonstrated by protocols which 
follow (see p. 127). There is not room in the female's body for more than 
a small feed, oft repeated, when she is laying ten to twelve eggs a day. Those 
who have fed lice but once or twice a day have therefore reached false 
conclusions regarding the egg-laying capacity of lice. 
Whereas corporis, maintained at 28-32° C., dry, in the thermostat, 
can be raised successfully when taken out and fed twice, or even at 
