782 E. A. MINCHIN. 
of the stain, but it is always better to work with an excess of 
the powder when grinding up, otherwise it is very difficult to 
obtain a saturated solution. 
“The solution when filtered should be kept in a good- 
stoppered bottle (and if a completely saturated solution has 
been obtained add 10 per cent. more alcohol-glycerine mixture). 
“Stain for five or ten minutes with the stain made up by 
mixing one part of distilled water with two parts of the 
glycerine-alcohol stain-solution. Rinse in distilled water. 
Fix for half to one minute in Unna’s elycerine-ether mixture, 
2 per cent. in distilled water. Rinse in distilled water. 
‘“ Differentiate and dehydrate in absolute alcohol. Should 
there be much precipitate this can easily be removed by a few 
drops of methyl alcohol or equal parts of absolute alcohol and 
xylol. Remove absolute alcohol with xylol and mount in 
Canada-balsam in the usual way.” 
I made a number of smears of blood containing T. lewisi 
in order to try the effects of Twort’s stain, and also used the 
stain mixed in different proportions with distilled water, and 
allowed to act for varying lengths of time. I could uot 
obtain good results with any smears fixed with osmic acid, 
either when smears previously exposed to osmic vapour were 
subsequently treated with absolute alcohol or sublimate-acetic 
or when smears were fixed direct in Flemming’s or Hermann’s 
fluids. On the other hand I got excellent results with smears 
fixed direct in sublimate mixtures, either sublimate-acetic, 
Schaudinn’s fluid, or Mann’s picro-corrosive, with or without 
formol (Pl. 25). As regards the application of the stain I 
did not obtain good results with weak mixtures used for a 
long time, but I got my best results by mixing the stain in 
equal quantity with distilled water, or by using two or even 
three parts of stain to one of distilled water and allowing the 
stain to act for from twenty minutes to an hour. I differen- 
tiated with 5 per cent. Unna’s glycerine-ether solution. I found 
that when the staining mixture was placed on the slide or 
coverslip a very dense precipitate formed on the smear, but by 
placing the stain im a suitable vessel such as a watch-glass, 
