The Washed Leukocytes 



This mixing, incubating, and spreading is done twice 

 once with the serum of the patient, and once with the normal 

 serum of the operator. The technic is the same each time. 



Fig- 99- A small incubator of special design for opsonic work (Miller) . 



In order that the enumeration of the bacteria taken up by 

 the leukocytes can be accomplished, it is next necessary to 

 stain the blood smears. This can be done by any method 

 that will demonstrate both 

 the bacteria and the cells. 

 For staphylococci and 

 similar organisms, Irish- 

 man's stain, Jenner's stain, 

 or J. H. Wright's stains 

 are appropriate. Marino's 

 stain, recommended by Fi S- 100. The smear (Miller). 

 Levaditi,* gives beautiful 



results. For the tubercle bacillus the spreads may be stained 



with carbol-fuchsin and counterstained with methylene- 



* "Ann. de 1'Inst. Pasteur," 1904, xvm, p. 761. 



