348 MBNINGOCOCCUS-^WNOCOCCUS— CATARRH ALLS GROUP 
other material from inflammations of the npper respiratory tract, in 
which IVIicrococcus catarrhalis is a primary or accessory factor, the 
organisms occur both within and without the pus cells. In the acute 
stages they are usually extracellular. The organism^ is non-motile, 
and it has no flagella. It forms neither spores nor capsules. It colors 
readily with ordinary anilin dyes, some cells more intensely than their 
fellows, and it is Gram-negative. 
Isolation and Culture.— The organism grows with moderate vigor 
upon agar; after twenty-four hours' incubation the colonies are small, 
translucent and gray. After three to four days the colonies are larger 
with an opaque center, the periphery being translucent. Old colonies 
tend to become somewhat brownish. Development is more vigorous 
in media containing blood, blood serum, or ascitic fluid. Hemolysis of 
the blood does not occur. The growth in gelatin is slow, and usually 
feeble. A slight turbidity develops in broth. Moderate development 
occurs in milk. Micrococcus catarrhalis grows best at 37° C.; re- 
stricted development takes place at 16° C; no growth can be detected 
at 43° C. 
Fig. 47. — Micrococcus catarrhalis and staphylococcus. 
Products of Growth.— The organism is culturally inert. It does not 
produce any demonstrable proteolytic enzymes, and it produces no 
acid in any sugar. Xo toxic products are known. Filtrates of broth 
cultures have no apparent action upon white mice. Xo pathogenesis 
for la])oratory animals has been detected. 
Human Pathogenesis.— Micrococcus catarrhalis has occasionally 
been reported as a causative factor in catarrhal inflammations of the 
upper respiratory tract, and even in atypical pneiunonia'^ and in 
bronchitis.'^ Ordinarily it is an opportunist found in the upper 
1 Ghon and Pfeiffer: Ztschr. f. klin. Med., 1902, 44, 262. 
2 Bernheim: Deutsch. med. Wchnschr., 1900, 26, 643. 
3 Ritchie: Jour. Pathol, and Bacteriol., 1901, 7, 1. 
