314 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Carnoy’s, and Hermann’s fluids. If there is any choice in these fix¬ 
ing reagents the two last are the best. The cells are perhaps a little 
shrunken.after the Carnoy’s fluid, but they stain very brilliantly. It 
proved exceedingly difficult to cut sections of the animal however 
fixed. The difficulties are two-fold : first, to cause the fixing, dehy¬ 
drating, and imbedding substances to penetrate successfully the thick 
chitinous skeleton, and secondly, to cut the chitin even when pene¬ 
tration is complete. The usual substitute for a section is some 
ragged pieces of chitin and a hole in the paraffin. Collodionization 
of each section, as recommended by Salmon and Stiles (: 02, p. 
381) met with no success, especially with the large specimens. 
Lest standing in alcohol make the sectioning more difficult, one 
lot of material was killed and carried as rapidly as possible through 
the reagents and into paraffin, where some specimens remained a 
few minutes and others seven days. Neither of these cut any better 
than others not so treated. 
Series which were serviceable for study of the general form of 
some of the organs were obtained by dissecting off the cuticula from 
museum specimens which had been in alcohol for ten years. The 
chitin seems to be free to some extent from the hypodermis in such 
specimens. Of course the cytological condition of such series is 
poor, but the sections are complete and perfect series are easily 
obtained. Each of the few complete series from fixed material was 
obtained from an animal which was nearly ready to moult, as was 
shown on examination of the sections. The outer shell was free 
from the animal and so its breaking did not injure the tissue within 
the thin and soft new chitin. Moreover, a more thorough penetra¬ 
tion of all the fluids was made possible through the holes and pores 
in the old, loosened cuticula. 
I would suggest that where sections are to be made through adult 
female ticks, they should be fixed in some warm fixing mixture and 
then left in strong alcohol some days to shrink away from the cu¬ 
ticula. After this treatment the chitin can be dissected off with 
fine needles, under a dissecting microscope, without serious injury 
to a great proportion of the specimens, and sections can be made as 
usual. 
The male skeleton is nearly as thick as that of the female, and 
being smaller, is more difficult to remove, and this method may 
prove impracticable for males. 
