CH. ix] OF TRANSMUTATION 131 



invasion in the living body. Lastly, even if the evidence 

 established the continuity between his original strains and 

 the new ones he obtained, the changes may possibly have 

 been merely examples of variation no greater in degree than 

 many that have been recorded by other observers. In other 

 words, the strains of atypical B. coli and those closely 

 resembling B. faecalis alcaligenes or S. faecalis, may con- 

 ceivably have been variants of his original strains of B. 

 typhosus whose true identity would have been disclosed by 

 more prolonged efforts to obtain reversion or more thorough 

 investigation with regard to their agglutination reactions. 



^ II. THE RELATIONSHIP BETWEEN MEMBERS OF THE ENTERITIS 

 GROUP OF BACILLI B. ENTERITIDIS " GAERTNER " AND THE 

 PARATYPHOID BACILLUS OF THE " AERTRYCK " OR " FLUGGE " 

 TYPE. 



The question of the specific character of these organisms 

 has been much discussed. They are generally recognised as 

 distinct species but evidence has been brought forward from 

 time to time suggesting that they may be transmuted one 

 into the other. 



A. Schmitt's experiments. 



Schmitt (1911), for example, claims that in certain experi- 

 ments conducted by him strains of the paratyphoid bacillus 

 of the Fliigge type became changed within the animal body 

 into the Gaertner type of bacillus. The details of the experi- 

 ments are briefly as follows. 



Experiment I. On July 17th, 21st and 28th he fed a 

 young calf on milk to which had been added (in amounts 

 varying from 1 to 50 c.c.) a broth culture of a Fliigge type of 

 organism without apparent effect, except that the blood 

 serum which previously did not agglutinate the organism now 

 did so in dilutions of 1 in 35. 



On August 3rd the same strain of organisms was injected 

 subcutaneously into the calf, with the result that the calf 

 became ill. An organism ("Pgst I") was isolated from the 



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