104 THE PATHOGENIC BACTERIA. 



VIII. Micrococcus Tetragenus. 



The Micrococcus tetragenus was obtained by Koch a. from 

 cavities of tuberculous lungs, b. in the sputum of phthisical 

 patients in the last stages of the disease, c. in the pus of 

 buccal and d. ocular abscesses. It has been found by Morinier 

 e. in the normal saliva and /. even in the saliva of newborn 

 babes. 



Morphology. A micrococcus with a diameter of about 1 

 mikron, formed in groups of 8 (tetrads) and enveloped by a 

 transparent gelatinous substance. 



Principal Biologic Properties. It is a facultative anaerobic. 

 On agar it forms thick granular spherical colonies of a white 

 or grayish color. It does not liquefy gelatin. It stains with 

 all the anilin dyes and readily by Gram's method. 



Pathogenesis. When inoculated into guinea-pigs subcutane- 

 ously, the animals die rapidly and abscesses are formed at the 

 point of inoculation. The micrococcus at the autopsy may 

 be found in all the organs and in the blood taken from the 

 heart. 



GONORRHCEA. 

 IX. Micrococcus Gonorrhoeas (Gonococcus). 



Discovered by Neisser in 1879, the gonococcus causes the 

 specific suppuration of gonorrhoea. 



Pathogenesis. This micrococcus, or diplococcus, as it is 

 generally called, has a special affinity for the urethral mucous 

 membrane, finding lodgement in the epithelial cells lining 

 this canal. It sometimes causes inflammation with or with- 

 out suppuration in other parts of the human body, such as 

 the conjunctiva, appendages of the uterus, in the peritoneum 

 and articulations. Cutaneous and muscular abscesses have 

 occasionally been found to be caused by the gonococcus. 



Morphology. These micrococci are usually found united in 

 pairs presenting the appearance of grains of coffee, the two 

 opposing sides being generally flattened or concave. In 

 stained preparations the flattened surfaces are separated by 

 an unstained interspace. The gonococci are found free in 



