276 TEXT-BOOK OF BACTERIOLOGY. 



In speaking 1 of the general qualities of the bacteria we have 

 become acquainted with a number of species differing- in some 

 respects, but obviously nearly related and belonging to certain 

 sharply-defined and well-characterized natural groups. 



The best proof of this fact is afforded in the following three 

 micro-organisms, resembling more or less closely the cholera vibrio, 

 sharing with it a series of peculiarities and evincing, in many 

 points, a striking similarity with it, although the differences exist- 

 ing are easily recognized. 



VIII. FINKLER-PRIOR'S VIBRIO. 



The first of these varieties of the vibrio was observed in the dis- 

 charges of patients having cholera morbus. This vibrio was origi- 

 nally considered by its discoverers to be identical with the genuine 

 comma bacillus. This opinion would, of course, have deprived that 

 vibrio of every significance. But it was soon ascertained that the 

 statements of those investigators were not well founded, and the 

 many points of difference between the two micro-organisms can 

 easily be made apparent. 



Finkler's and the cholera bacteria greatly resemble each other 

 in the shape of the individual germs. But Finkler's vibrio is, as a* 

 rule, somewhat larger, thicker, and coarser than Koch's. It de- 

 velops more rarely into spirilla which scarcely ever become as long* 

 as those of the cholera bacteria. It increases in hanging drops, at 

 ordinary temperature, to dense sjvarms; it resists the influence of 

 oxygen like the genuine comma bacillus. 



On the plate Finkler's bacterium is distinguished from the 

 cholera vibrio by an extraordinary growth coincident with an ex- 

 tensive liquefaction of the gelatin. The usual three dilutions do not 

 even suffice, and only on the fourth or fifth plate will well-isolated 

 colonies develop. 



When observing them with a diffuse light and the naked eye, 

 they appear first as small white dots in the depth of the gelatin. 

 They rapidly push forward to the surface, the dissolution of the 

 gelatin begins, and there arise circular depressions, proceeding' 

 toward the middle, in the shape of saucers. On the second day they 

 appear at least as large as lentils, their contents consisting of a, 

 turbid fluid of gray translucency. The border is sharply defined from 

 the solid part of the medium, but there are no other peculiarities. 



Under the microscope these colonies appear as yellowish-brown 

 dense masses, possessing a very fine but entirely uniform granula- 

 tion. Even with low magnifying power an active movement, an 



