COCCACE^E. SPHERICAL BACTERIA. 133 



Special Introductory Remarks Concerning the Coc- 

 caceae. Spherical Bacteria. 



1. Since almost all the varieties presented, with the 

 exception of the Micr. gonorrhoeas, stain with the ordinary 

 anilin dyes and by Gram's method, we usually state 

 nothing regarding the staining properties, except when 

 they can not be stained by Gram's method. 



2. When no mention is made offlagella and spores, they are 

 absent. 



3. No mention is made of the intense stain with watery 

 solutions of anilin dyes, which occurs with all varieties, 

 and a similar statement would have to be always repeated. 

 It is strongly recommended, when it is desirable to obtain 

 the cement substance between the bacterial cells unstained 

 (capsules), to employ a dilute aqueous solution of anilin dyes, 

 or after staining with stronger solutions to employ dilute 

 acetic acid as a decolorizing agent, or to use Gram's 

 method. This is obligatory in the case of sarcinae and 

 diplococci in order to render the line of fission in dividing 

 cocci visible, etc. (An exception is the gonococcus.) 



4. Since all varieties of the genus micrococcus not infre- 

 quently occur as diplococci, tetrads, and short chains, we 

 have only said anything regarding the grouping when there 

 is something special to notice. 



5. For an exhaustive discussion upon suppuration and 

 the part played by micro-organisms in the same, see Kurt 

 Miiller, C. B. xv, 735, and Poliakoff, C. B. xvm, 33. 



FAMILY L COCCACEAE. SPHERICAL 

 BACTERIA. 



Family diagnosis and genera scheme, see page 122. 



i. Streptococcus (Billroth). 



The cells divide only in one direction of space at right 

 angles to the direction of growth, so that if the multiply- 

 ing cells remain attached to each other, shorter or longer 

 rosary-like chains are formed. Often the chain appears 

 to be be built up from distinct pairs. Chains are formed 

 with most constancy in bouillon ; upon gelatin and agar, 



