EXPERIMENTAL DEMONSTRATION OF OPSONINS 



61 



FIG. 25 



substances which prepare bacteria for subsequent phagocytosis. 

 Whether these substances are originally formed in the blood serum, 

 or whether they are furnished by decomposing leukocytes, as 

 Metchnikoff and his followers claim, is likewise not settled. 



Experimental Demonstration of Opsonins. The 

 presence of these substances in the blood serum 

 can be shown by the following experiments. In 

 one test leukocytes washed in physiologic salt 

 solution and a freshly prepared bacterial emulsion 

 are mixed in equal proportions and placed in 

 the incubator for one-half hour. In a simulta- 

 neous test, washed leukocytes are mixed with 

 blood serum and a freshly prepared bacterial 

 emulsion, and the mixture is treated as above. 

 After one-half hour, microscopic preparations 

 are made from both mixtures. It will be found 

 that in the mixture where blood serum was 

 lacking phagocytosis has not taken place, while 

 in the other test where blood serum was present 

 a good deal of phagocytosis has occurred. This 

 clearly shows the influence of the opsonins of 

 the blood serum. 



FIG. 26 



j | 



Opsonizing pipette into 

 which serum, washed leuko- 

 cytes, and a bacterial emul- 

 sion have been drawn up. 

 (Miller in Therapeutic 

 Gazette.) 







Opsonic incubator. 



