Professor Koch on the bacteriological diagnosis of cholera ; Water-filtration and cholera ; and, The cholera in Germany during the winter of 1892-93 / translated by George Duncan.

  • Robert Koch
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: Professor Koch on the bacteriological diagnosis of cholera ; Water-filtration and cholera ; and, The cholera in Germany during the winter of 1892-93 / translated by George Duncan. Source: Wellcome Collection.

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    bacteriology, and it is not necessary, I suppose, to indicate in detail what a dangerous part such mildest cases may play in the spreading of cholera, and how important their detection must be.* The method originally described by me, of which, as is well known, cultivation on gelatine plates forms the basis, has, as very soon appeared in the course of last year's epidemic, not always adequately fulfilled the demands just stated. As re- gards certainty, indeed, it left nothing to be desired, for not a single instance of its failure in ordinary cases in skilful and practised hands has ever come to my knowledge. Only in the above-mentioned mildest cases, in which the excreta contain very few cholera-bacteria, cases which have become accessible to us only by the methods to be described below, does the gelatine-plate-method not suffice. But the point in which the method hitherto in use left most to be desired was rapidity of demonstration. If one proceeded in the ordin- ary way, and used plates on which the colonies must have developed so far that they presented a characteristic aspect, and were large enough to admit of the making of microscopic preparations from a single colony, the investigation generally lasted, according to the conditions of temperature, from a day and a half to two days. In many cases, however, when the task was the first diagnosis in a place, a still longer period, varying from two to five days, elapsed before it was possible to declare with certainty whether the disease was Asiatic cholera or not. Such delays, however, are not to be ascribed to the method, but to the inexperience of the investigators. I could give a good number of such instances, but will restrict myself to one case, which has become the best known of all, and also led probably to the most serious * These mildest cholera-cases, in which cholera-bacteria were found in the solid excreta of apparently healthy persons, occurred only among groups of persons who were equally exposed to infection, and some of whom had the disease in a severe form. Among persons who were not exposed to infection at all nothing of this kind has ever been found. One must therefore regard these cases as genuine cases of cholera, and cannot use them as arguments against the specific character of the cholera-bacteria.
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