34 FREDERICK EBERSON 



production in the usual carbohydrate concentrations is at a maximum 

 after 24 hours. In any case the antigenic properties of both strains are 

 not in agreement, and the cultural tests seem to bear out this difference. 

 Mellon's flavidus may be a subspecies, but it differs from Morse's type 

 too markedly to go by the same species name. 



Closer agreement exists in the case of C. hoagii, for which we find 

 on "the one hand neither group agglutinins nor cross-fixation for C. 

 hofmanni and C. xerosis, while, on the other hand, there are both 

 cross-fixation and group-agglutination with the flavidus antigen. C. 

 hofmanni shows group agglutinins for C. hoagii and C. flavidus (Mel- 

 lon), but not for C. xerosis. 



TABLE 3 



AGGLUTINATION TESTS AND COMPLEMENT FIXATION STUDY 



Antigen 



The figures and signs enclosed in parentheses represent the highest dilution in which 

 partial agglutination occurred, and the decimals indicate the amount of antigen in mg. which 

 was necessary for fixation with the different serums. Absorption experiments with a strain 

 of Morse flavidus omitted. 



There is no apparent correlation between the reactions in carbo- 

 hydrates and the antigenic properties. Nonspecific agglutinins appear 

 to be readily absorbed, whereas the specific agglutinins are left intact. 



Morse's complement fixation study and the group agglutination tests 

 are shown in Table 3. 



III. PLEOMORPHISM OF DIPHTHEROIDS, MUTABILITY 



OF TYPES, AND A METHOD FOR DETERMINING 



MUTANTS 



VARIABILITY OF BACTERIA 



Bacteria are unicellular organisms which are produced from other 

 like organisms by the process of fission an act in which the entire 

 parent substance may be said to divide itself equally into two fractions, 

 both of which constitute the resulting pair of bacteria. Under such 

 conditions the offspring cannot possess what was not present in the 

 parent. This, in essence, is the pure line concept of bacteria and 

 implies the descendants from any single bacterial cell. The hereditary 

 characteristics of such a biotype do not change as a result of changed 



