26 



THE NATURE OF BACTERIA. 



to separate low plants from animals, all of the characters 

 which distinguish the two groups among higher types dis- 

 appearing when we come to the microscopic forms. The 

 microscopist' has, however, after long study, reached the 

 conclusion that bacteria are to be regarded 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 func- 

 tions, nor whether they are beneficial or detrimental. 



MULTIPLICATION OF BACTERIA. 



Method. The common method of reproduction of bac- 

 teria 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 immense practical importance. In addition to their 

 multiplication 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 



FIG. 8. 



Showing the formation of spores. 



bacterium commonly breaks up and the oval or spherical 

 bodies are set free. These are spores. They are resting 

 forms and their function seems to be to enable the bacteria to 

 exist through conditions of adversity. They have very 



