VIL] MICROCOCCUS. 59 



Some species are specially characterised by dividing into 

 a dumb-bell ; if each of the elements divides again trans- 

 versely into a dumb-bell ; a group of four (tetrade or sarcina- 

 form) is thereby produced. Some species are occasionally 



FIG. 13. PART OF A CONVOLUTION OF CHAINS OF MICROCOCCI ; FROM AN 

 ARTIFICIAL CULTIVATION STARTED WITH THE SERUM OF A BLISTER OF A 

 RABBIT'S EAR. 



met with, particularly in products of air-contamination, in 

 which the four individuals are closely pressed against one 

 another, and then each assumes more or less the shape of a 

 cube, a true sarcina (see below). But each of these cubes 



2 2 f * ' f 2 5 



st l S2 SI 



~ a* ft go e$ 



8 * f gl 85 



FIG. 14. GIANT MICROCOCCI, FROM FIG. 15. SARCINA-MICROCOCCUS, FROM 



SAME PUTRID SPUTUM AS IN PRE- AN ARTIFICIAL CULTIVATION. 



vious FIGURES. rp, , r , 



i. Ine elements of each sarcma-group 



1. Dumb-bells. of four appears single. 



2. Division of dumb-bells into sarcina. 2. The elements incompletely divided 



3. Incomplete division into sarcina. into secondary groups. 



3. Each element of the previous groups 

 has divided into four small micro- 

 cocci. 



divides into four small micrococci arranged as a small sarcina, 

 so that a sarcina-within-sarcina-form results. 



In many instances the individual members resulting from 

 division remain closely adherent without any definite arrange- 



