TECHNIQUE 



The opsonic teciinique used in this research -was essen- 

 tially the same as that originally employed by Wrirht and 

 Douglas (17). Certain modifications and refinements, however, 

 were introduced which seemed to insure ,c;reater uniformity in 

 the results, and to make this generally confusing technique 

 more dependable and satisfactory. 



The blood providing the cells was received into a centri- 

 fuge tube containing several volumes of citrated calt solution. 

 Before sedimentation the cells were uniformly suspended by re- 

 peated suction and ejection with a pipette. This process was 

 repeated before each centrifugation and is a most effective 

 means of preventing the aggregation of the platelets .around the 

 leucocytes. Tne centrifugation was accomplished at a speed 



which permit Led the sediu.entation of the white cells in four to 



is 

 five minutes without throwing down the platelets. This^most 



important for it eliminates the platelets from tne leucocytic 



layer and prevents packing of the white cells. The washings 



were repeated three times and the leucocytes suspended in a 



volume of physiological salt solution equal to one third t.:e 



the 

 original volume of blood. After standing for one hour, cells 



A 



were uniformly suspended by a gentle continued agitation of 

 the tube and all samples of any one experimental series were 

 taken immediately. it was early observed that the ingesting 

 capacity of phagocytes was not always as reliable and vigorous 

 if they were used immediately after washing as when they were 



(6) 



