168 LABORATORY COURSE IN SERUM STUDY 



Experiment 2 



THE OPSONIN UNITES WITH THE BACTERIA, NOT WITH THE 

 LEUCOCYTES 



In two small centrifuge tubes mixtures are made with the same ma- 

 terials employed in Experiment 1, as follows : 



(1) Bacterial suspension 0.1 c.c. 

 Fresh guinea pig serum 0.2 c.c. 

 Salt solution 0.7 c.c. 



(2) Leucocyte suspension 0.2 c.c. 

 Fresh guinea pig serum 0.2 c.c. 

 Salt solution 0.6 c.c. 



These tubes are allowed to stand at 37 C. in water bath or incu- 

 bator for 30 minutes. Then centrifugalize vigorously and wash sedi- 

 ment once in salt solution. 



To the bacterial sediment of (1) add : 



Leucocyte suspension 0.2 c.c. 



Salt solution 0.3 c.c. 



To the leucocyte sediment of (2) add : 



Bacterial suspension 0.1 c.c. 



Salt solution 0.4 c.c. 



Allow the tubes to stand for 30 minutes at 37 C. Then make 

 smears and examine as in Experiment 1. 



Materials: 



Serum, leucocytes, bacterial Capillary pipettes with rubber 



emulsion as described. nipples. 



Microscope slides. Jenner's stain. 



2 Centrifuge tubes. 5 -inch test tubes. 



LESSON XXVII 

 DETERMINATION OF OPSONIC INDEX (WRIGHT) 



PREPARE the following reagents : 



1. Bacillary suspension. Make suspension of Staphylococcus 

 aureus culture in salt solution. Allow to stand in test tube for clumps 

 to settle out. Transfer upper portion to separate test tube. 



2. Leucocyte suspension. Obtain 15 or more drops of blood from 

 finger tip in centrifuge tube containing about 10 c.c. of citrate solution. 



