PATHOGENIC MICROCOCGI NOT HERETOFORE DESCRIBED. 311 



10. STAPHYLOCOCCUS SAL.IVARIUS PYOGENES. 



Obtained by Biondi (1887) from, an inoculation abscess in a guinea-pig- 

 injected subcutaneously with saliva from a child suffering from scarlatina 

 anginosa. 



Morphology. Spherical cocci, 0.3 to 0.5. ft in diameter, usually solitary in 

 the pus of abscesses or in irregular agglomerations. 



Stains best by Gram's method. 



Biological Characters. Grows at a comparatively low temperature 

 (12 to 14 C.), and more rapidly in. the incubating oven. In gelatin stick 

 cultures, at the room temperature, growth occurs along the line of punc- 

 ture, and at the end of eight days liquefaction commences in the form of 

 a funnel, at the bottom of which little, white, shining masses accumu- 

 late, while at the surface of the liquefied gelatin a white, viscid layer forms. 

 In gelatin plates spherical, well-defined, opalescent, whitish colonies are 

 formed, which cause a tardy liquefaction of the surrounding gelatin. Upon 

 agar-agar the growth is rapid, in the form of a thick layer along the line of 

 inoculation in streak cultures, which has a breadth of about one millimetre 

 at the end of twenty -four hours in the incubating oven, and presents an 

 orange-yellow color at the centre, fading out to white at the margins. The 

 yellow color is not by any means as pronounced as in similar cultures of 

 Staphylococcus pyogenes aureus, and liquefaction of gelatin is much slower. 



Pathogenesis. Produces a local abscess when inoculated into dogs, rab- 

 bits, guinea-pigs, or mice. When injected into the anterior chamber of the 

 eye of rabbits, hypopyon, followed by spontaneous perforation of the cor- 

 nea, resulted. Injected into the circulation of a guinea-pig (0.2 to 0.4 cubic 

 centimetre) it gave rise to general infection, and death at the end of eight to 

 ten days. 



11. MICROCOCCUS OF PROGRESSIVE TISSUE NECROSIS IN MICE. 



Obtained by Koch (1879) from mice inoculated subcutaneously with putrid 

 blood. 



Morphology. Round cells, 0.5 A in diameter, united in chains, or at times 

 in crowded masses. 



Biological Characters not given. 



Pathogenesis. Causes necrosis of the tissues in the vicinity of the point 

 of inoculation in mice, which extends rapidly and causes the death of the 

 animal in about three days. The blood and internal organs remain free from 

 micrococci. (Possibly a very pathogenic variety of Streptococcus pyogenes?) 



12. MICROCOCCUS OF PROGRESSIVE ABSCESS FORMATION IN 



RABBITS. 



Obtained by Koch (1879) from rabbits 

 inoculated with putrid blood. 



Morphology. Minute cocci, about 0.15 " 

 in diameter, usually associated in thick, 

 cloud-like zooglcea masses. 



Biological Characters not given. 



Pathogenesis. In rabbits an extensive 

 abscess forms in the vicinity of the point of in- 

 oculation, and the animal dies in about twelve 

 days. The walls of the abscess are formed of a 

 thin layer of micrococci associated in zoog- 

 loea masses; the interior contains finely gran- 

 ular, cheesy material, in which the cocci ap- 

 pear to have degenerated and perished. The tf _ _ 



contents of the abscess injected into other FIG. 96. Micrococcus of progressive 

 rabbits produce a similar result. The micro- tissue necrosis in mice; section of the 

 coccus does not invade the blood. o> ; c h5 cart Be el ' s; "' 8treptococci - 



