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(3N THE NITRlEYmG PROCESS AND ITS SPECIFIC FERMENT. 
destitute of organic matter, to which we have referred, so that its sudden transference 
to rich, nutritive media, like broth and gelatine-peptone, might not unnaturally he 
expected to produce a profound change in its organisation. 
We have already shown how the capacity of growing in gelatine was entirely lost 
through this long residence in the dilute ammoniacal medium, which capacity was 
only restored by a preliminary cultivation in broth, similarly, we presume that 
cultivation in broth and gelatine may greatly diminish, and in some cases possibly 
extinguish, the nitrifying power of the organism. 
It is particularly noteworthy that tlie ammoniacal solutions inoculated from the 
broth cultures, on inoculation into gelatine, yielded no growth whatever, hut gave the 
characteristic tardy growth in broth, in this respect, as in the microscopic form of the 
organism they contained, precisely resembling the pure nitrifying solutions from 
which these broth-cultures were originally obtained. 
