THH STRUCTURE OF TRYPANOSOMA LEWISI. 771 
the trypanosomes are scarcely if at all deformed. ‘he body 
maintains an even, slender form, differing only from the type 
in size. The minute details of the nuclei, blepharoplast, and 
flagellum are very well seen after sublimate mixtures, and 
especially after picro-corrosive, better, indeed, than with any 
other fixative in my opinion. 
(2) Staining Methods. 
I have made trial of a number of staining methods on films 
preserved in various ways, and have obtained results which 
may be considered from two points of view. Some staiming 
methods give good results generally, and yield what I may 
term “show” preparations —that is to say, preparations 
which one would not be ashamed to demonstrate to students 
or to strangers. Other stains give results which are quite 
useless considered as preparations for purposes of demon- 
stration, but which may be quite interesting as micro-chemical 
reactions. I will discuss in detail the three staining methods 
that have given me the best results generally, namely the 
Romanowsky stain in its various modifications, Heidenhain’s 
iron-hematoxylin method, and T'wort’s combination of neutral 
red and licht-griin; after which I will deal briefly with other 
stains I have tried. 
(1) Romanowsky stain.'—In applying this methed I have 
always used Giemsa’s modification; | obtain the stain made 
up in the fluid condition from Griibler, and for actual use I 
mix the stain with distilled water in the proportion of one 
drop of the stain to 1 c.c. of water. The preparations are left 
im from three to eighteen hours. Osmic-fixed preparations 
are apt to stain very darkly, and require a much shorter time 
than those simply fixed with alcohol. The preparations when 
taken out of the stain are washed with distilled water, treated 
for a few seconds with Unna’s tannin-orange (obtained from 
‘T use the term “ Romanowsky stain” as a general term for the 
combination of stains, of which the methods of Leishman, Giemsa, ete., 
are special modifications, in application or substance. 
