40 MASTITIS OF THE COW 



the division is so rapid that the full length is never reached 

 and thus through dividing the breadth of the cell is greater 

 than its length. 



In animal bodies the organism frequently presents a 

 wide capsule. The capsule appears to occur principally on 

 the short chains, especially the diplococci type. 



The capsule formation is most distinct in mice (in the 

 liquid of the spleen) . In the other laboratory animals and 

 in our domesticated animals it is indistinct as a rule. In 

 man it is very distinct (diplococcus pneumoniae). It is 

 visible after staining with carbol-methylene blue or with 

 Gram's method (Fig. 6). 



Fig. 6. — The pathogenic streptococci in milk sediment. Gram. (150). Three different types. 



The streptococcus is easily stained with the common 

 anilin dyes as well as by Gram's method, in which decolor- 

 ization with alcohol need not be long, however. It is less 

 Gram positive than the staphylococcus, but more so than 

 the bacillus pyogenes. The streptococcus is inmiotile. 



Cultivation. — It grows best at body temperature (ca. 

 38° C.) and appears not to grow under 18° C. 



It grows aerobically and anaerobically but inclines more 

 toward the anaerobic tendency. 



In order to isolate streptococci in pure culture, it is 

 usually necessary that the culture medium contain serum. 

 If one has first cultivated it on this medium it is easier to 

 grow it on media without serum. 



For the purpose of isolation I pour plates of sei-um- 



