n8 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
It is necessary to keep the blue solution for some days in a warm place until 
it has acquired the well-known purple tint. The thick film of blood on the slide is 
dried, and then very gently washed until all the colour has disappeared from it. A 
drop or two of the eosine solution is now placed upon it (without previous drying), 
and allowed to remain for a minute. Next, a drop or two of the blue solution is run 
in, and allowed to remain from fifteen to thirty seconds. Lastly, wash with a very 
gentle stream of water for a minute or so ; dry, and mount or examine. 
The student must practice the method in order to obtain perfect results. He 
should aim at staining the parasites in a typical manner without staining the stromata 
of the red corpuscles. If the preparation is so much overstained that the stromata 
are deeply coloured, the preparation is not so elegant, though it may still be 
useful. 
For crescents and other large pigmented malarial parasites, I use the weakest 
possible staining, sufficing just to give a taint tint to the organisms without obscuring 
their melanin. With trypanosomes the blue must be applied somewhat longer than for 
malaria parasites. It should be noted that for Haemamoeba vivax the method has 
not proved very satisfactory owing to the indecisive staining of the chromatin. 
It is advisable to use a high ocular, say Nos. 4, 8, for finding the smallest 
organisms. 
