38 TRYPANOSOMA 
side down, and the whole gently heated over a spirit lamp 
or bunsen flame until the steam rises, when the green scum 
is about to make its re-appearance, remove the coverglass 
with a pair of forceps, wash in water and afterwards in very 
dilute alcohol; finally dry and mount in Xylol Balsam. 
In specimens so prepared all the morphological characters 
of the organisms are very clearly demonstrated. As to their 
permanency I have some preparations which I made in 1886 
in London and which still show all the peculiar features 
of this organism. 
The above stains are admirably adapted for photo- 
micrographic purposes, but for studying the structure of such 
delicate organisms I find the recently introduced blood 
staining methods of Romanowsky, Leishman and Jenner to 
give the most satisfactory results. By either of these 
methods, in which eosin and methylene blue dissolved in 
pure methyl alcohol are employed, different parts of the 
organism have an affinity for selecting in varying degrees one 
or other of the combined stains. 
Of the three methods I prefer Romanowsky’s: the 
blood to be examined is spread in a very thin film on a 
cover-glass, and allowed to dry spontaneously, which is 
sufficient to fix the specimen without passing through the 
flame, allow a few drops of stain to remain on the film for 
five minutes, then add an equal quantity of freshly distilled 
water, mixing gently for another three minutes, wash 
thoroughly in distilled water, dry in the air, and mount in 
xylol balsam. 
