THE MICROCOCCUS CATARRH ALIS 365 



gitis is secondary to infection of the lungs, bronchi, the nasal cavities 

 or their accessary sinuses. 



4. The colon bacillus, the typhoid bacillus, that of bubonic plague and 

 of glanders, all may cause a complicating purulent meningitis. 



5. In isolated cases of meningitis complicating otitis media and other 

 infections, other bacteria, such as the micrococcus tetragenus, the bacillus 

 pyot'i/uncux, etc., may be found 



Micrococcus Catarrhalis (R. Pfeiffer). 



Micrococci somewhat resembling meningococci are found in the 

 mucous membranes of the respiratory tract. They are believed at 

 times to excite catarrhal inflammation of the mucous membranes. 

 These are at present included under the designation of micrococcus 

 catarrhalis. 



Microscopic Appearance. They usually occur in pairs, sometimes in 

 fours; never in chains. The cocci are coffee-bean in shape and slightly 

 larger than the gonococcus, and are negative to Gram's stain. 



The micrococci are not motile and produce no spores. 



Cultivation. They grow between 20 and 40 C., best at 37 C. and 

 less rapidly at somewhat lower temperatures. They develop on ordin- 

 ary nutrient agar as grayish-white or yellowish-white, circular colonies of 

 the size of meningococci. The borders of the colonies are irregular and 

 abrupt as though gouged out. They have a mortar-like consistency. 

 On serum-agar media the growth is more luxuriant. Gelatin is not 

 liquefied. Bouillon is clouded, often with the development of a pellicle. 

 Milk is not coagulated, but dextrose serum media may be. Gas is not 

 produced. 



Location of Organisms. In the secretion of normal mucous mem- 

 branes they are occasionally present. In certain diseased conditions of 

 the mucous membranes they may be abundant. 



Pathogenic Effects in Animals. For white mice, guinea-pigs, and 

 rabbits, some cultures are as pathogenic as meningococci, while others 

 are less so. 



Differential Points Separating them from the Meningococci. These 

 organisms have undoubtedly been at times confused. Some assert that 

 the meningococci grow only above 25 C. Many cord cultures of 

 meningococci grow below this point. Some assert that the meningo- 

 cocci will not grow on 5 per cent, glycerin agar. Many undoubted 

 cultures do. The probability is that the organisms described by dif- 

 ferent writers as micrococcus catarrhalis were not all the same variety, 

 and some of them were meningococci. 



