28 METHODS OF EXAMINATION. 



cocci come under consideration, it will be observed that there is 

 evidence of their multiplication in their mode of arrangement, and a 

 multiplication which at once removes them from the domain of 

 inorganic nature. They are arranged in pairs (see Fig. i) — diplococci 

 — as though one had grown from the other by a process of cleavage or 

 partial fission. This process may have been continued so that, instead 

 of a single pair, there is a chain of some length made up. of cocci of 

 the same shape and of equal size, the fission taking place in the same 

 plane at each successive division. In other cases the process of 

 fission may take place in planes alternately at right angles to one 

 another, in which event, as pointed out by numerous observers, 



* Sir &k *.«* r ^ &%» ' 







M^K 



J.T.T. 



Fig. i. — Pus from an acute abscess at time of evacuation. Dried 

 and treated with methyl violet. ( x 700.) 



a. Pus corpuscles between which may be seen the thin film of 



coagulated albuminoid material. 



b. Pair of micrococci — Diplococcus. 



c. Chains of micrococci — Streptococci. 



d. Sets of four — Tetrads. 



peculiar tetrads are formed. Micrococcus tetragonus or Sarcina vcntri- 

 culi may be taken as examples of this mode of fission. 



