GENERAL CHARACTERISTICS OF BACTERIA. 37 
shaped forms, as frequently seen in the diplococcus of 
pneumonia, or the opposite, as in the diplococcus of 
gonorrhea, where the cocci appear to be flattened 
against one another. Those cells which divide in one 
Fig. 1. 
Single coccus, grouped irregularly. Diplococcus of pneumonia, with sur- 
Staphylococcus. rounding capsule. 
Fig. 3. 
Streptococcus. Tetracoccus. 
direction only and remain attached are found in pairs 
(diplococci) or in shorter or longer chains (streptococci). 
Those which divide in two directions, the one at right 
angles to the other, form bunches of four (tetrads). 
