248 



A MANUAL OF BACTERIOLOGY 



If cultures are obtained, the fermentation tests (see below) may 

 be applied. 



N.B. The greatest caution must be exercised in declaring a case 

 free from infection on the ground of NEGATIVE results of the examina- 

 tion. 



The Characters of the Chief Gram-negative Cocci (Gordon) 



+ = acid. 



= alkali. 



no action. 



Micrococcus catarrhalis 1 



This organism occurs in the nose and throat in cases of catarrh, 

 and particularly in the " influenzal cold " (see " Influenza "), in 

 bronchial catarrh, and occasionally in other conditions and in well 

 people. Morphologically it occurs in pairs and tetrads, often 



1 See Gordon, Brit. Med. Journ., 1905, vol. ii, p. 423 ; Arkwright, 

 Journ. of Hygiene, vol. vii, 1907, p. 145. 



