202 OPSONIC INDEX 



10. Examination of the stained films with the oil-immersion ob- 

 jective of the microscope will show that polynuclear leukocytes have 

 collected more toward the edges and the end at which the spreading was 

 completed. The individual leukocytes, however, should be separated 

 from one another (Figs. 54 and 55). 



11. The edge of the film is examined, and the number of bacteria 

 found in each series of five consecutive phagocytes is noted. If the 

 technic has been satisfactory, no great divergence should be found in 

 the count of each set of five cells. 



FIG. 52. BLOOD FILMS FOR PHAGOCYTIC COUNTS. 



The first slide (on the extreme left) is too thick and honeycombed, due to a 

 greasy slide and large drop of blood; the second is likewise thick and uneven; the 

 third is too thin, and was spread with too small an amount of blood and with the 

 spreader held too upright; the fourth (extreme right) is a satisfactory film; it was 

 spread on a clean slide, is even, smooth, and of the proper thickness. 



12. If the films are satisfactory, divide 100 phagocytes into groups 

 of 20. The average ingest of each group should not show a difference of 

 over 10 per cent., otherwise the technic has been faulty and it is neces- 

 sary to count 250 phagocytes or to repeat the test. If divergence is 

 due to the fact that every now and then one cell has a considerable 

 higher ingest than others and the bacteria are well separated, hyper- 

 activity of the cell is probably the cause. If the bacteria are all clumped 

 together, it must be assumed that there has been a lack of care in prepar- 

 ing the bacterial emulsion or that agglutinin is present in the serum, 

 and the test must be repeated with fresh precautions. 



