1896 



THE MICROSCOPE. 



135 



000 per square inch and 15,025,000,000,000 per cubic 

 inch. This means that if human beings were no larger 

 than these bacteria we couhl put the population of the 

 world in a box an inch each way, the population of 

 more than 8,000 similar worlds on top and shut down 

 the cover without being afraid of hitting anyone on the 

 head. 



The Form of Bacteria. — In the above illustration it is 

 presumed that the dimensions of the organism are equal 

 in any and all directions; this is true in one type and such 

 a bacterium is called a micrococcus, or little sphere. The 

 other types are the bacillus, or little rod, and the spiril- 



m" 



lum, or bent rod, wliich may take the form of a comma or 

 even of the corkscrew. Between these forms there are 

 many intermediate ones. 



The Manner of Reproduction of Bacteria. — One of 

 the characters common to all of the different bacteria is 

 their method of reproduction, in fact it is upon this one 

 characteristic that they have all been placed in a single 

 class and called by the botanists schizomycetes, or fission 

 fungi. If a single cell, provided with the necessary con- 

 ditions of nourishment, is watched under a microscope it 

 will soon be seen that the cell begins to elongate and 

 when this has proceeded some little distance it can be 



