Report on the Bacteriology of Water. 



211 



Kraus contributed a valuable paper in 1887.* After pointing out 

 that, important as are the results of Meade Bolton, and of Wolffhugel 

 and Riedel, to science, they have very little practical utility, because 

 (1) they concern chiefly sterilised waters, which do not occur in the 

 open, and (2) the temperatures employed were too high to be com- 

 pared with what happens in daily life, this author proceeds to 

 describe his results with ordinary drinking waters kept at about 

 10-5° C. 



He found that the typhoid bacillus under these circumstances soon 

 succumbs to the rapidly increasing " water forms," and that it was 

 eliminated in seven days. 



Koch's cholera spirillum could not hold its ground more than two 

 days at this temperature, in contest with the rapidly dominating 

 aquatic forms.t 



Even Bacillus anihracis disappeared from these waters in four 

 days. 



Kraus concludes that much more must be put down to the direct 

 effect of the competing bacteria in such cases, than to the quality of 

 the water or the original number of forms contained in it. 



We may remark in this connexion that it bears out what is also 

 deducible from the preceding results of Bolton and Wolffhugel and 

 Riedel,J and further, that this view of Kraus is distinctly supported 

 by our knowledge of the competing action of dominant forms, due to 

 their successful seizure of oxygen, food materials, &c, on the one 

 hand, and to the toxic actions of their metabolites on the other. § It 

 is not improbable that sterilisation by heat acts both by setting free 

 food materials in the form of dead bacteria, as well as by destroying 

 such toxic principles. 



Gartner|| found that typhus bacilli will live for long periods in 



. * " Ueber das Verhalten pathogener Bacterien im Trinkwasser " (' Arch.f. Hyg.,' 

 vol. 7, 1887, p. 234). 



t These and similar results with mixtures of microbes must be received with 

 great caution, as already pointed out, for it has been proved by GTruber (' Wiener 

 Mediz. Wochensch.,' 1887, JSTos. 7 and 8) that on placing the cholera spirilla in 

 contact with ordinary putrefaction bacteria, the latter, in the first instance, gain an 

 enormous numerical ascendency over the cholera spirilla; but if the struggle 

 between the two be sufficiently protracted, the cholera spirilla can, at the close of 

 the putrefaction process, be still found in the living state. 



% Bolton, however, made no experiments with unsterile water; and Wolffhugel 

 is far from convinced as to the destruction of typhoid bacilli by water bacteria, 

 putting down their absence on the plate cultures rather to experimental difficulties of 

 finding them. It is not impossible that the experimental difficulties account for these 

 results of Kraus. 



§ See also note on p. 203 regarding Garre and Miquel's results. 



|| " Pathogene und Saprophytische Bakterien in ihrem Verbaltniss zum Wasser, 

 insbesondere zum Trinkwasser " (' Correspondenz-Blatter des allgem. Aerztl. Yereins 

 von Thuringen,' 1888, Nos. 2 and 3). 



