116 
TENTH REPORT. 
Fig. 5. — Drawing out long end of blood pipette to form 
pricking needle. 
of the blood pipette and loosen the blood from the glass with a platinum 
wire. If the blood is to be transported some distance seal off the curved 
end of the blood pipette after the blood has been 
shaken down into the straight end. In sealing either 
end of the pipette it is well to so grasp the rest of the 
pipette that the portion containing blood is completely 
covered by the fingers, in order to protect the blood 
against undue heat. In obtaining blood for this work 
it is better not to squeeze or knead the finger. 
The glass pricking needle is thoroughly aseptic, 
causes very little pain, and gives a free flow of blood. 
It is best made in the small pilot flame, provided 
with some Bunsen burners to keep the gas alight 
when the main flame is turned off. Hold the capillary 
tube in this flame until it softens, then remove from 
the flame and rapidly draw the softened part out into 
a hair (see Fig. 5). Break off the flexible portion, ready 'for use,° wMi short 
and the sharp point remaining is the pricking needle poking needle °Jt othS 
(see Fig. 6). end. 
Beginners who are not accustomed to making blood examinations some- 
times have difficulty in obtaining an adequate flow of blood. If the following 
points are observed, one puncture will usually supply blood enough for both 
the serum and the corpuscles. 
The glass needle should not be too fine: The rubber tube should be so 
wound (from the base to the tip) as to produce good compression in the 
finger. 
Make one good puncture, not several half-hearted attempts. 
Have the citrate solution and the blood pipette ready so that the blood 
will not be lost. 
As soon as the puncture is made break off the needle end by pressing it 
against any hard object, as it is liable to be plugged, in which case the blood 
will not flow into the capsule. 
Putting Up the Test . — Take up in an opsonizing pipette equal quantities 
of blood-corpuscles, bacterial emulsion, and blood serum in the order named, 
separating them by means of air bubbles (see Fig. 13). Drive the liquids 
