MICHIGAN ACADEMY OF SCIENCE. 
1 25 
Fig. 22. — The drop ready to spread. 
Fig. 23. — The sraeiir. 
The average number of bacteria found in the phagocytes gives t lie pha- 
gocytic count. The phagocytic count of the blood to be tested, divided by 
the phagocytic count of the pool serum, gives the opsonic index (see Table lj. 
