The Washed Leukocytes 



279 



layer of blood-corpuscles to this mark, then removing the 

 tube, permits the column to as- 

 cend a short distance. Next he 

 draws up the bacterial suspension 

 to the same point, withdraws the 

 tube, and permits the column to 

 ascend; then draws up the serum 

 to be taken to the same point; 



Fig. 84. Special blood pipette (Miller). 



thus in the same capillary tube 

 he has three equal volumes of 

 three different fluids, separated by 

 bubbles of air. It is next neces- 

 sary to mix these, which is done 

 by repeatedly expelling them upon 

 a clean glass slide, and redrawing 

 them into the tube, as shown in 

 Fig. 86. After thus being thor- 

 oughly mixed, the fluid is once 

 more permitted to enter the capil- 

 lary tube and come to rest there. The end is now sealed in 



Fig. 85. Opsonizing pi- 

 pette containing blood-cor- 

 puscles, bacterial emulsion, 

 and blood-serum (Miller). 



