120 
TENTH REPORT. 
a triangular file and breaking it across. This broken end 
has very sharp edges, and, with a few trials, one with the 
proper curvature is usually obtained. Then break off the 
corners and the spreader is complete. In using such a 
5 spreader, it should be drawn very lightly or it will be soon 
| spoiled by having the corners worn off. Such a spreader 
- is brought in contact with the drop to be spread, moved 
1 slightly to distribute the drop uniformly across the end 
~ of the spreader, and then, while held at an angle of about 
5 20 degrees above the horizontal, is drawn along the slide 
= until the drop is exhausted (see Fig. 21.) The drop 
| should not be so large as to- extend to the end of the 
| slide (see Fig. 22). A good smear should be uniform in 
-z consistency, and most of the leucocytes should be found 
r along the edges and at the end. For convenience in count- 
| ing it is well to have the smear terminate abruptly, and 
OT - not be drawn out into threads or irregular forms (see Fig. 
•g 23). 
CO 
O 
O 
o 
tSj 
o 
o 
tp 
5 
72 
— « 
0 
1 
oo 
O 
Fig. 14. — Mixing the fluids by repeatedly drawing 
them into the pipette and expelling them on to the 
slide. 
Staining . — Any good stain that brings out in sharp relief the bacteria 
and white blood-corpuscles can be used. For tubercle, carbol-fuchsin with 
methylene blue as a counter-stain is usually employed. For staphylococcus 
and other germs, Hastings’ or J. H. Wright’s stain may be used.* 
Two rods of brass or of glass, about 2\ inches apart, 'supported over a sink, 
make a convenient rack for staining tubercle (see Fig. 24). The slides 
are placed across these rods, and the fixing, staining, washing, etc., done 
* Directions for preparing these stains maybe found in the Journal of Experimental Medicine, 
1905, Vol. 7, page 265 (Hastings), and the Journal of Medical Research , 1902, Vol. 7, page 138 
(Wright). 
