THE MICROSCOPE IN MEDICINE AND SANITATION. Y11 
even smear. After drying in the air this is ready for 
staining. 
One of the most satisfactory differential blood-stains 
is Wright’s modification of Leishman’s method, described 
in the Journal of Medical Research for January, 1902 
(volume VII, p. 138). The somewhat complicated pro- 
cedure for making this stain and some discussion of 
the philosophy of-its action must be sought in the original 
paper; but the student will find its application easy. 
The dried film is covered with the solution of the dye in 
methyl alcohol for one minute and water is added, drop 
by drop, until the mixture becomes semi-translucent 
and a yellowish metallic scum forms on the surface. 
This mixture is allowed to stand on the preparation 
for two or three minutes and then washed off in distilled 
water till the film has a yellowish or pinkish tint in its 
thinner portions. 
The slides thus stained, dried, and mounted in balsam 
should show the various types of blood-cells beautifully 
differentiated. The red corpuscles, or erythrocytes, are 
orange or pink in color and about 7.5 w in diameter. 
The white cells may be divided into three classes accord- 
ing to the relation which their nuclei and granules bear 
to the constituents of the stain. The eosinophiles or 
oxyphiles are cells containing matter which takes such 
acid stains as eosin. Stained with the Wright stain, these 
appear faintly blue with a dark lilac-colored nucleus 
and numerous large reddish granules. They are double 
the size of the erythrocytes. The basophiles are cells 
which take basic stains and are of two varieties. Small 
