240 



APPLIED IMMUNOLOGY 



diagnostic and prognostic capacity would appear to 

 be limited, ( 1 ) because other methods, as the cutane- 

 ous allergic reactions, are simpler if not more reliable, 

 and (2) owing to a certain amount of error, even with 



FiQ. 35. — Showing effect of variable concentrations of bacterial suspension on 



determinations of opsonic index. . bacterial suspension centrifuged for 10 



minutes, then dilution of supernatant suspension so that 1 c.mm. contained approxi- 

 mately 10,000,000 bacteria. , bacterial suspension centrifuged for 10 minutes. 



.bacterial suspension centrifuged for 10 minutes and supernatant suspension 



diluted with 3 volumes of 0.85 per cent, saline solution. , bacterial suspension 



standardized by McFarland's "nephelometer." 



experienced workers, small variations may not be de- 

 pendable, although it renders great service at times, in 

 cases of mixed infection, enabling the immunologist 

 to choose for inoculation the particular responsible 



