578 APPLICATION OF METHODS OF BACTERIOLOGY 



little, until the proper degree of consistency is obtained (that 

 of ordinary nutrient gelatin). This part of the process is 

 best conducted in a culture-dish. If it is desired to separate 

 the colonies, as in an ordinary plate, the inoculation and 

 mixing of the material introduced must be done before 

 gelatinization is complete; if the material is to be distributed 

 over only the surface of the medium, then the mixture 

 must first be allowed to solidify. 



By the use of the silicate-gelatin Winogradsky has isolated 

 from the gelatinous film in the bottom of fluids undergoing 

 nitrification a bacillus which he believes to be associated 

 with the nitro-monas in the nitrifying process. 



Our knowledge of these organisms is as yet too imperfect 

 to permit of a complete description. What has been said 

 will serve to indicate the direction in which further studies 

 of the subject should be prosecuted. (For further details, 

 the reader is referred to the original contributions and to 

 current literature on the subject.^) 



In addition to the bacteria concerned in the various trans- 

 formation of nitrogen, there are occasionally present in the 

 soil micro-organisms possessing disease-producing properties. 

 Conspicuous among these may be mentioned the bacillus 

 of malignant edema (vibrion septique of the French), the 

 bacillus of tetanus, and the bacillus of symptomatic anthrax 

 {Rauschbrand (Ger.); charbon symptomatique (Fr.)). It is 



' Winogradsky, Annales de I'Institut Pasteur, 1890, tome iv; 1891, 

 tome V. 



Jordan and Richards, Report of State Board of Health of Massachusetts 

 Purification of Sewage and Water, 1890, ii, 864. 



Frankland, G. C. and P. F., Proceedings of Royal Society, London, 

 1890, vol. xlvii. 



Winogradsky and Omeliansky, Ueber den Einfluss der organisaten Sub- 

 stangen auf der arbeit der nitrifizierenden Mikroben, Centralblatt filr 

 Bakteriologie, 1899, Abt. ii, Bd. v, S. 329. 



