MICHIGAN ACADEMY OF SCIENCE. 
119 
Fig. 10. — Ssaling needle end of blood pipette. 
in Figs. 17 and 18. To avoid air bubbles when drawing the mixture into 
the pipette for the last time, have the end of the capillary tube square-cut, 
hold the pipette perpendicular to the slide, and draw in slowly (see Fig. 19). 
Making the Smear . — Remove the opsonizing pipette from the incubator; 
break off the*healed tip; drive the contents on to a slide; mix, as shown in 
Fig. 14, then place a small drop on one end of a slide (see Fig. 22) and spread 
out into a film by means of a special spreader. The spreading is usually 
done by means of another slide, from 
Fig. 11. — Blood shaken 
down into sealed end of 
blood pipette. 
which the corners have been broken 
Fig. 12. — Blood pipette 
after cent rifugalization, 
showing serum separated. 
The upper end must after- 
wards be broken off to give 
access to the serum. 
off, in order that the smear may not cover the entire width of the slide (see 
Fig. 20). A good smear greatly facilitates the otherwise laborious work of 
counting, and each worker usually develops his own favorite way of accom- 
plishing this result. Perhaps as good a form of spreader as any is one with 
the spreading edges sharp and smooth and the spreading end concave (about 
1^ diopters). It is conveniently made by nicking the edge of a slide with 
