Abstract
Vaccines prepared from 115 strains of anaerobic coryneforms and other organisms were tested in mice for their reticulostimulating ability as judged by the degree of spleen hypertrophy produced after ip injection. Almost all vaccines caused a statistically significant increase in spleen weight, but the ability to produce spleen ratios (test mean wt:control mean wt) of 4 or more was confined to Propionibacterium acnes and P. avidum strains. P. acnes, type 11, gave high spleen ratios more frequently than strains of any other type.