270 



PHARMACEUTICAL BACTERIOLOGY 



from five to ten days to develop the immunizing effects, and their use was 

 accompanied bytmore or less severe local as well as systemic reactions 



FIG. 67. Counting the bacteria in standardizing bacterins. This chart shows the 

 count of bacteria and of red blood cells in twenty successive fields of the microscope. 

 The number of red cells counted (308) is to the number of bacteria counted (224) as the 

 number of red cells per cubic centimeter in normal blood (5,000,000,000) is to the number 

 of bacteria per cc. in the suspension (3,636,000). This count (3,636,000) divided by the 

 count desired in the final dilution(4oo, 000,000) gives the number of times (9) this sus- 

 pension must be diluted to bring it to the desired dilution. (Parke, Davis J& Co.). 



(anaphylaxis) . These undesirable qualities are said to be avoided or over- 

 come by the use of the so-called sensitized bacterins or sero-bacterins. 



