THE BIOLOGY OF BACTERIA 9 



which show a flattening of the side of each micrococcus 

 which is in relation to its partner. Perhaps the diplococci in 

 an even greater degree than the micrococci respond to ex- 

 ternal conditions both as regards size and shape. It must 

 further be borne in mind that a dividing micrococcus assumes 

 the exact appearance of a diplococcus during the transition 

 stage of the fission. Hence, with the exception of several 

 well-marked species of diplococci, this form is somewhat 



9 9 



VARIOUS FORMS OF BACTERIA 



i. Micrococcus 2. Diplococcus 3. Streptococcus 



4. Staphylococcus 5. Leuconostoc, showing Arthrospores 



6. Merismopedia 7. Sarcina 8. Bacilli 



9. Spirillum 



arbitrary. The third kind of micrococcus is that formed by 

 a number of elements in a twisted chain, named streptococcus 

 (ffTpSTtros, twisted). This form is produced by cells dividing 

 in one axis, and remaining in contact with each other. It 

 occurs in a number of different species, or what are supposed 



