PRODUCERS OF ABSCESS, CELLULITIS, ETC. 473 
scesses. Its presence has also been noted in the pus of 
empyema following pneumonia. 
Morphology. Micrococci having a diameter of about 
ly, which divide in two directions, forming tetrads, 
and bound together by a transparent, gelatinous sub- 
stance, enclosing the cell like a capsule. In cultures 
the cocci are seen in various stages of division as large, _ 
round, undivided cells, in pairs of oval elements, and 
in groups of three and four (Fig. 60). When the divis- 
Micrococcus tetragenus. X 1000 diameters. 
ion is complete they remind one of sarcine in appear- 
ance, except that they do not divide in three directions 
and are not built up like diminutive cotton bales. 
. This micrococcus stains readily with the ordinary ani- 
line dyes; the transparent gelatinous envelope is only 
_feebly stained. It is not decolorized by Gram’s method. 
Biological Characters. The growth of this micro- 
coccus is slow under all conditions. It grows both in 
the presence and absence of oxygen; it grows best from 
35° to 38° C., but may be cultivated also at the ordi- 
nary room-temperature—about 20° C. 
