28 AGRICULTURAL BACTERIOLOGY. 



It is not likely that the name will ever be changed. The dis- 

 tinction of Bacillus and Bacterium, based upon the presence of 

 flagella, is a convenient one, but its adoption would produce 

 considerable confusion in the terms which have been com- 

 monly accepted in the last few years. At all events in most 

 bacteriological literature the term Bacillus does not have the 

 significance above mentioned and simply refers to any rod- 

 shaped bacterium. It should be noted also that whereas the 

 word Bacteria refers to the whole group of fission fungi which 

 we are to study, the genus Bacterium has reference only to a 

 small division of rod-shaped bacteria. 



3. Spiral Bacteria. Spirillum. In this group the rods are 

 spirally coiled to form either long or short spirals (Fig. 4, c}. 

 They are not so abundant as the cocci and rod forms, al- 

 though some of them are of importance in agriculture, inasmuch 

 as they play an active part in the decay of organic tissues. 

 They are sometimes motile and sometimes stationary. The 

 only two divisions of the group that we need to notice are as 

 follows : 



Spirillum. Ordinary spiral rods, stiff and inflexible (Fig. 

 4, c, i). 



Spirochteta. Spiral rods which are flexible like a spiral 

 spring (Fig. 4, c, 2). 



4.. Higher Bacteria. Cladotlirix, Lcptothrix, Strcptothrix, 

 Actinomyces. (Fig. 7.) Under this head are included a few 

 forms of fungi which resemble other bacteria in some respects, 

 but differ in others. They are composed of threads which are 

 commonly larger than the threads of bacteria and which may 

 show frequent branching, a characteristic not usual in bacteria. 

 They also have a peculiar method of forming reproducing 

 bodies. The group is not one of very great importance. 



This classification gives only what are usually recognized as 

 the genera of bacteria. A further classification of the group 

 into species is at the present time in a condition of the greatest 



