PYOGENIC BACTERIA. 381 
the most common microorganism upon the surface of the body, and 
that “itis very often present in parts of the epidermis deeper than 
can be reached by any known means of cutaneous disinfection save 
the application of heat.” With reference to this coccus Welch 
says: 
‘So far as our observations extend—and already they amount to a 
large number—this coccus may be regarded as a nearly, if not quite, con- 
stant inhabitant of the epidermis. It is now clear why I have proposed to 
eall it the Staphylococcus epidermidis albus.’ It possesses such feeble pyo- 
genic capacity, ag is shown by its behavior in wounds as well as by experi- 
ments on rabbits, that the designation Staphylococcus pyogenes albus does 
not seem appropriate. Still, I am not inclined to insist too much upon this 
point, as very probably this coccus, which has hitherto been unquestionably 
identified by Bossowski and others with the ordinary Staphylococcus pyo- 
genes albus of Rosenbach, is an attenuated or modified form of the latter 
organism, although, as already mentioned, it presents some points of differ- 
ence from the classical description of the white pyogenic coccus.” 
According to Welch, this coccus differs from Staphylococcus pyo- 
genes aureus not only in color, but also in the fact that it liquefies 
gelatin more slowly, does not so quickly cause coagulation of milk, 
and is far less virulent when injected into the circulation of rabbits. 
It has been shown by the researches of Bossowski and of Welch 
that this coccus is very frequently present in aseptic wounds, and 
that usually it does not materially interfere with the healing of 
wounds, although sometimes it appears to cause suppuration along 
the drainage tube, and it is the usual cause of ‘stitch abscess.” 
Bossowski, in fifty cases of wounds treated antiseptically, obtained 
bacteria from the discharges in forty, and in twenty-six of these 
eases he found Staphylococcus pyogenes albus; Staphylococcus au- 
reus was found nine times, Streptococcus pyogenes in two, and vari- 
ous non-pathogenic bacteria in eight. In forty-five laparotomy 
wounds examined by Ghrisky and Robb, in which strict antiseptic 
precautions had been observed, bacteria were found in thirty-one, and 
in nineteen of this number Staphylococcus albus was present, 
Staphylococcus aureus in five, Bacillus coli communis in six, and 
Streptococcus pyogenes in three. 
STAPHYLOCOCCUS PYOGENES CITREUS. 
Isolated by Passet (1885) from the pus of acute abscesses. In thirty- 
three cases examined it was found associated with Staphylococcus albus in 
two and with Staphylococcus albus and Streptococcus pyogenes in one. 
In its morphology this coccus is identical with the two preceding species 
from which it is distinguished by the formation of a lemon-yellow pigment, 
instead of a pofen or orange-yellow as in Staphylococcus aureus. The 
pigment is only formed in the presence of oxygen. This coccus is said by 
Frankel to liquefy gelatin more slowly than the previously described species 
—Staphylococcus aureus and Staphylococcus albus. 
As to its pathogenic properties we have no definite information. It is 
included among the pyogenic bacteria because of its occasional presence in 
