316 PATHOGENIC MICROCOCCI 



bubble forms near the surface of the gelatin ; very slight liquefac- 

 tion occurs in the immediate vicinity of the line of growth, and after 

 a time the grayish-white thread sinks into an irregular mass, lying 

 at the bottom of the puncture. Upon nutrient agar scarcely any de- 

 velopment occurs. Upon potato the growth is abundant, in the form 

 of a pale-yellow, circular layer, and the culture gives off the peculiar 

 odor above described. 



PatJiogenesis. When inoculated into guinea-pigs general infec- 

 tion and death result. In sheep and goats it produces a local in- 

 flammatory oedema and sometimes necrosis of the tissues. In horses 

 inoculated subcutaneously an inflammatory oedema first occurs, fol- 

 lowed at the end of from four to six weeks by the development of new 

 growths in the connective tissue, resembling the tumors found in 

 cases of the disease in the animal from which the micrococcus in 

 question was first cultivated. These tumors contain characteristic 

 mulberry-like conglomerations of colonies made up of the coccus. 



20. MICROCOCCUS OF MANFREDI. 



Synonym. Micrococcus of progressive granuloma formation. 



Obtained by Manfredi (188G) from the sputum of two cases of 

 croupous pneumonia following measles. 



Morphology. Oval micrococci, having a diameter of 0.6 to 1.0 p 

 and from 1.0 to 1.5 /* in length ; usually associated in pairs, and oc- 

 casionally in short chains containing three or four elements. 



Stains with the aniline colors and by Gram's method. 



Biological Characters. Aerobic ; does not liquefy gelatin. 

 Upon gelatin plates forms small, spherical colonies, at first grayish- 

 white, which spread out upon the surface as thin, transparent plates, 

 which by transmitted light have a bluish, by reflected light a pearl- 

 gray color. Later these become thicker and have a pearly lustre. 

 Under the microscope (forty to fifty diameters) the colonies are seen 

 to be slightly granular and the margins have an irregular outline. 

 In gelatin stick cultures a scanty growth occurs along the line of 

 puncture, and a rather thin and limited growth about the point of 

 inoculation. Upon blood serum a thin, greenish-yellow layer, which 

 has irregular margins and a slightly granular, shining surface, is 

 developed. The growth upon potato, at 37 C., is scanty, and con- 

 sists of a very thin, moist layer, which has a yellowish color and is 

 slightly granular. Growth occurs in favorable media bouillon, 

 gelatin at temperatures of 18 to 48 0., but ceases at a temperature 

 of 48 to 50 C. 



Pathogenesis. Pathogenic for dogs, rabbits, guinea-pigs, mice, 

 and birds. In mammals the principal pathological appearance re- 

 sulting from infection consists in the formation of " granulation tu- 



