770 E.-A. MINCHIN. 
absence of formol, but got the impression that the fixation 
was rather better, and the stain sharper, after use of the 
mixture containing formol. 
Mann’s fluid gave me very uniform results. The trypano- 
somes show no periplast-line and appear slender. The 
blepharoplast and flagellum show up with remarkable clear- 
ness, especially after iron-hematoxylin, and this appears to 
me the method of choice for the study of these structures. 
With all the sublimate-containing mixtures that have been 
tried, a marked diminution of size is apparent in the never- 
dried preparations as compared with the type (compare 
especially figs. 1-8 with figs. 16,35,and 79), The shrinkage 
is on the whole greatest after the picro-corrosive mixture; 
the disappearance of the periplast-line after fixation with 
picro-corrosive indicates, perhaps, a certain amount of collapse 
in the cytoplasmic body. 
As already pointed out above, the shrinkage is scarcely 
perceptible if the trypanosomes have been allowed to dry 
off after exposure to the osmic vapour before fixation in the 
sublimate mixture. Figs. 70 and 73 show this plainly when 
compared with figs. 14, 15, 16, ete. 
The facts indicate further that the shrmkage is due not 
only to the action of the fixative but also to the subsequent 
processes which the trypanosomes pass through, namely, first 
the staining process, secondly the dehydration and clearing 
preparatory to mounting in Canada-balsam. It can be 
observed, for example, that the Romanowsky stain, when 
used on trypanosomes which have not been dried, seems to 
shrink them more than do other stains, such as iron-hema- 
toxylin or T'wort’s stain; compare, for instance, figs, 19, 20, 
82-84 with figs. 21, 22, from a film which, after having been 
fixed and stained in Giemsa’s stain without drying, was dried 
off after the stain; the trypanosomes are shrunk to a ludi- 
crous extent in the latter case. 
Although the trypanosomes are distinctly diminished in 
size and general proportions after sublimate fixation (when 
never dried), the shrinkage appears to take place evenly, and 
