THE PUTREFACTIVE BACTERIA. 297 



and therefore the examples already cited, being the species most 

 frequently met with, must suffice. Moreover, we have already 

 mentioned others of this class in previous paragraphs. One of 

 these, viz., the Bacterium Zopfii, discovered by KURTH (I.) in the 

 stomachs of fowls and shown in Fig. 31, is, according to Czaplewski, 

 identical with Proteus Zenlteri. This note appears in an abstract 

 of a work by CH. MOUGINET (I.), who, also, minutely examined a 

 number of putrefactive bacteria. HOLSCHEWNIKOFF (I.) described 

 a fission fungus closely allied to Proteus vulgaris, which, from its 

 faculty of producing sulphuretted hydrogen, has been named 

 Proteus sulfureus. 



Only one more species will be dealt with here, and that briefly, 

 viz., Bacterium coli commune, which is an invariable inhabitant of 

 the alimentary canal of the human subject (and of all the higher 

 animals hitherto examined), and constitutes the most important 

 of the bacteria present in faeces. This parasite was first described 

 by TH. ESCHERICH (I.) as a slender short rod, 0.4 p broad, the 

 length varying with the conditions of nutrition and cultivation, 

 but mostly measuring 2-3 p, though occasionally it decreases to 

 0.5 fji. By some authors this fission fungus is named Bacillus 

 coli communis and Colon bacillus. Like the Proteus species, it 

 generally appears as double rods, but its movements are sluggish 

 and laboured. It does not liquefy gelatin. In media containing 

 sugar it can develop even in the absence of oxygen, and liberates 

 a gas which according to FREMLIN (I.) consists of two- thirds 

 carbon dioxide and one-third hydrogen. No development of 

 endospores has hitherto been detected. In its manner of growth 

 in artificial media this organism agrees in many particulars with 

 Bacillus typlii abdominalis. Consequently they are extremely 

 hard to differentiate, and this makes the bacteriological examina- 

 tion of water a particularly difficult operation when the presence 

 of typhus bacilli has to be quantitatively determined. A further 

 complication is imparted by the extreme sensitivity of B. coli com- 

 mune to modifications in the conditions of cultivation, and by its 

 great tendency to form varieties. For instance, a number of races 

 of B. coli commune are now known, which, under certain circum- 

 stances, are not merely saprophytic, but also pathogenic. A more 

 detailed treatment of this question would occupy too much of our 

 space, and besides, the matter is fully recorded in Tiemann-Gartner's 

 work on Water Analysis. A synopsis of the most important 

 researches of Escherich, Kohler, Baginsky, Bischler, and others, on 

 the methods of nutrition of B. coli commune and its powers of 

 decomposition, was prepared by M. IDE (I.) in 1891. The facts 

 brought to light since that date will be found in the several 

 yearly volumes of A. Koch's " Jahresbericht." 



We will now briefly refer to the subject of intestinal putre- 

 faction. Mention has been made in a previous paragraph of the 

 fundamental difference between the processes of decomposition 



