382 PYOGENIC BACTERIA. 
the pus of acute abscesses, although it has heretofore only been found in as- 
sociation with other microérganisms. 
MICROCOCCUS PYOGENES TENUIS. 
Obtained by Rosenbach (1884) from pus in three cases out of thirty-nine 
examined. 
Morphology.—Micrococci, somewhat irregular in size, but larger than 
Staphylococcus albus, and seldom associated in masses. Frequently the in- 
dividual cocci present the appearance of consisting of two deeply stained 
masses separated from each other by a paler interspace. Cultures upon the 
surface of nutrient agar form a very thin, transparent layer of about one 
millimetre in breadth along the line of inoculation; this resembles a thin 
layer of varnish. f 
Pathogenesis undetermined. (Micrococcus pneumoniz croupose ?) 
STREPTOCOCCUS PYOGENES. 
Synonyms.—Micrococcus of erysipelas (Fehleisen) ; Streptococcus 
erysipelatos ; Streptococcus of pus ; Streptococcus longus (Von Lin- 
gelsheim). 
Obtained by Fehleisen from the skin involved in cases of erysipe- 
las (1883), and by Rosenbach (1884) and Passet (1885) from the pus 
of acute abscesses. The characters of the ‘‘ streptococcus of erysipe- 
las” of Fehleisen and the ‘‘ Streptococcus pyogenes” of Rosenbach 
and Passet are generally admitted to be identical, although some 
bacteriologists still describe them separately and cultures from the 
two sources are still retained in bacteriological laboratories under the 
names originally given them. 
Rosenbach found Streptococcus pyogenes alone in fifteen cases, 
and associated with staphylococci in five cases, out of thirty-nine 
cases examined of acute pus formation. Passet, in thirty-three 
similar cases, obtained the streptococcus alone in eight and associated 
with staphylococci in two. Subsequent researches show that this 
micrococcus is frequently, if not constantly, present in puerperal 
metritis ; that it is the most frequent microédrganism associated with 
ulcerative endocarditis ; that it is frequently present in diphtheritic 
false membranes, and especially in those cases of diphtheritic inflam- 
mation which are secondary to scarlet fever and measles (Prudden). 
Numerous investigations made by bacteriologists during the past few 
years indicate that this isa very important and widely distributed 
pathogenic microérganism. It has also been frequently found upon 
exposed mucous surfaces—mouth, nose, vagina—of healthy in- 
dividuals. ° 
According to the researches (1891) of Von Lingelsheim, the Strep- 
tococcus pyogenes differs from Streptococcus erysipelatos in be- 
ing pathogenic both for mice and rabbits, while the latter is patho- 
