30 AGRICULTURAL BACTERIOLOGY. 



character which would naturally lead to their being called 

 animals. Biologists find it very difficult to separate low plants 

 from animals, all of the characters which distinguish the two 

 groups among higher types disappearing when we come to 

 the microscopic forms. The microscopist has, however, after 

 long study, reached the conclusion that bacteria are to be re- 

 garded as plants, basing his conclusion chiefly upon their 

 form and their method of reproduction by spores. It is a 

 matter of no significance for our purpose whether we call them 

 animals or plants, for this classification gives us no suggestion 

 as to their functions, nor whether they are beneficial or detri- 

 mental. 



MULTIPLICATION OF BACTERIA. 



Method. The common method of reproduction of bacteria 

 is by simple division (Fig. 3). But although this method of 

 multiplication is common to all bacteria, there is another 

 method frequently found which, for certain reasons, is of im- 

 mense practical importance. In addition to their multiplica- 

 tion by division some species of bacteria form spores. The 

 contents of the organism collect in one or more small rounded 

 masses (Fig. 8), after which the body of the bacterium com- 



FIG. 8. 



Showing the formation of sp> 



monly breaks up and the oval or spherical body is set free. 

 These are spores. They are resting forms and their function 



