DE BARY AND HUEPPE'S CLASSIFICATION. 93 



employed by us to designate only a well-defined form-phase of 

 cell, viz., the cylindrical bacterial cell, the length of which is at 

 least double the breadth. Hueppe's system, however, applies the 

 generic name Bacillus only to such rods as have been proved 

 capable of developing endospores. This definition has not yet 

 been accepted by the majority of bacteriologists ; hence it happens 

 that newly discovered rod-shaped species of fission fungi are still 

 occasionally assigned to the genus Bacillus, although the describer 

 may have no knowledge whatever as to their capability of forming 

 endospores. The author has not considered it within his province 

 to change this nomenclature, and therefore this fact must be borne 

 in mind in perusing the present work. It should also be re- 

 membered that in the following paragraphs the generic name 

 Bacillus Hueppe's definition notwithstanding means nothing 

 more than that the species of bacterium so entitled exhibits, pre- 

 ferentially and under normal conditions, the bacillus form of growth. 

 A comprehensive collection of the relative dimensions and 

 forms characteristic of growth in various nutrient media, &c., 

 of about three hundred species of fission fungi was prepared by 

 EISENBERG (I.), and may be advantageously employed as an aid to 

 determining whether any species under examination is identical 

 with any known species. A descriptive table of eighty-seven 

 of the bacteria of most frequent occurrence in drinking- and 

 utilisable water is given by ADAMETZ (I.). Reference may also be 

 made here to the very valuable book of TIEMANN and GARTNER (I.) 

 in connection with the bacteriological analysis of water. FRANK- 

 LAND and WARD (I.) give a comprehensive account of the literature 

 published up to the year 1882 on the bacteria occurring in natu- 

 ral and mineral waters, and a comparative investigation into the 

 distribution of a number (twenty- eight) of well-known bacterial 

 species in various well-waters has been made by W. MIGULA (III.). 



70. Pathogenic, Chromogenie, and Zymogenie 

 Bacteria. 



The attempts hitherto made to obtain a method of classifica- 

 tion of bacteria have always been restricted to the morphology of 

 the organisms themselves. It will now be well to remember that 

 the attention of Applied Mycology is preferentially directed to the 

 influence exerted by the fungi on their nutrient media. The 

 interest aroused by these organisms has always, from the outset, 

 had its practical side. Bearing this in mind, it will be readily 

 conceivable that, long before the establishment of Cohn's first 

 classification, there had appeared in the literature of the subject a 

 division of bacterial species into three main groups : pathogenic, 

 chromogenic, and zymogenic bacteria. 



It is quite unnecessary to remark that this grouping is just 

 as faulty as the division of the Schizomycetes into cocci, bacilli, 



