122 
TENTH REPORT. 
2. Stain with carbol-fuchsin about one minute (carbolic acid 5, fuchsin 1, 
water 100). The slides should be heated, while staining, until steam is 
given off. Wash. 
Fig. 16. — Mechanical 
control for opsonizing 
and other pipettes de- 
vised by Dr. W. H. 
Hutchings. 
Fig. 17. — Special pipette holder for opsonic or other 
small-calibered pipettes. The long handle'gives a firm 
pistol-grip on the pipette while the screw enables one to 
control the column of liquid very accurately. The glass 
pipette can be introduced into the soft rubber stopper 
as readily and quickly as into a rubber nipple. 
3. Decolorize in 24 per cent sulphuric acid. Wash. 
4. Treat for a few seconds with 5 per cent acetic acid to reduce the 
prominence of the red blood cells. Wash. 
5. Counter-stain with alkaline methylene blue (methylene blue 1, sodium 
carbonate 1. water 200). Wash lightly and dry. 
Method of Using Hastings' or Wright’s Stain . — Without any preliminary 
fixing, cover the film with the stain and allow to stand forty-five seconds. 
Add, carefully, drop by drop, about an equal volume of distilled water, mix, 
and let it stain for two minutes. Wash with distilled water and dry. 
