CLASSIFICATION. 23 



sion in three directions. This form resembles in appearance 

 a bale of cotton or a dice. 



Staphylococcus : the most common form, in which the cocci 

 occur in irregular groups of varying numbers and without 

 definite arrangement. The name is derived from the Greek 

 ffTcupubj, and is given to this form because of resemblance to 

 a bunch of grapes. 



Streptococcus: chains of cocci. When division occurs in 

 only one direction, with adhesion or attachment of the indi- 

 vidual members, chains of varying length are formed. Some 

 authors distinguish a streptococcus longus and a streptococcus 

 brevis, that is, long chain and short chain ; and a few, a 



FIG. 6. 



a. Bacilli in pairs, b. Single bacilli, c and d. Bacilli in threads. 

 e and /. Bacilli of variable morphology. (Abbott.) 



streptococcus conglomeratus. When the chain is composed 

 of diplococci, it is called a streptodiplococcus. 



Ascococcus and leuconostoc are two very unusual groupings 

 of cocci. In the former the cocci are associated in globular 

 or lobulated masses held together by a firm, gelatinous, intra- 

 cellular substance. In the second variety the cocci grow in 

 chains or masses, and are surrounded or enclosed by a very 

 thick and tough gelatinous capsule. 



The bacilli (Fig. 6) are rod-shaped or filamentous bacteria, 

 motile or non-motile, flagellated or not, reproducing them- 

 selves both by fission and sporulation. They are not sub- 

 divided into groups, but exhibit considerable variation of 



