THe Hoa Lovust 715 
This fluid was first used by Pampel (1914:298) in his work on the female 
Ichneumonidae, and he found that it kept the tissue soft and elastic for 
dissecting purposes. After chloroforming, a small slit was cut in the side 
of the abdomen to allow the preserving fluid to penetrate more rapidly. 
Owing to the toughness of the cuticula, dissections could not be made 
on slides, and so the lice were fixed to the top of a thin layer of paraffin 
in the bottom of a watch glass and covered with physiological salt solution. 
Sealpels with curved blades, microscope scissors, and fine needles were 
used, and all dissections were made under a Zeiss binocular. After some 
practice the different systems could be removed intact and placed on 
slides in a drop of salt solution, where the parts could be arranged in the 
desired way and fixed in position with Bless’ fluid according to the method 
followed by Patton and Cragg (1913:718-720). The material could then 
be carried through the alcohols and stained in toto. The best result in 
such staining has been obtained with Grenacher’s borax carmine, the 
stain being allowed to act for from twenty-four to forty-eight hours. 
In dissecting organs for sectioning, the physiological salt solution was 
replaced by the medium in which the tissue was fixed. 
In the study of the epithelium of the digestive tract, the alimentary 
tract was dissected out and prepared for imbedding in paraffin. In order 
to cut more than one stomach at a time, the method learned by Minchin 
from fellow workers in the Zoological Station at Naples in 1891, and 
used by Minchin and Thomson (1915:508) for sectioning the stomachs 
of fleas in their study of the rat trypanosome, was tried. Their method 
consisted of cutting thin free-hand sections of amyloid liver, arranging 
three stomachs on it with the anterior borders level, and fixing them in 
position with a drop of albumen fixative. This block could be oriented 
easily, but it was found more satisfactory to simply imbed single alimentary 
tracts. 
In sectioning whole lice it was necessary to double-imbed in celloidin 
and paraffin, and three methods were followed, all of which gave equally 
good results. The slow method of celloidin imbedding, beginning with 
a thin solution and gradually increasing the thickness until the object 
was sufficiently permeated with celloidin to be hardened in chloroform 
and carried on to paraffin in the usual way, was first tried. Then, in order 
to shorten the period of infiltration, a modification of Gilson’s rapid 
method (Lee, 1905:131) was substituted. At the same time the oil- 
