Sl?rn WAT/ON.
the suppurative changes in wounds entered the exposed
tissues principally from the atmosphere, and that the
hands and instruments of the operator, while certainly
means of infection, were secondary in importance to it.
The researches of more recent date, however, have
shown not only that the atmosphere cannot be disin-
fected, but also that the air of ordinarily quiet rooms,
while containing the spores of numerous saprophytic
organisms, very rarely contains many pathogenic bac-
teria. We now also know that a direct stream of air,
such as is generated by an atonmer, causes more bacteria
to be conveyed into a wound than would ordinarily fall
upon it, thereby increasing instead of lessening the dan-
ger of infectigu, It may therefore be stated, with a
reasonable amount of certainty, that the atmosphere is
rarely an important factor in the process of suppuration.
We have already called attention to the fact that
various micro-organisms are so intimate in their relation
to the skin that it is almost impossible to get rid of them,
and have cited in this relation the experiments of Welch,
Robb, and (Jhriskey, whose method of disinfecting the
hands has been recommended as the best. The investi-
gations of these observers have shown that, no matter
how rigid the disinfection of the patient's skin, the
cleansing of the operator's hands, the sterilization of
the instruments, and the precautions exercised, a certain
number of wounds in which sutures are employed will
always suppurate. The cause of the suppuration is a
matter of vast importance in surgery and in surgical bac-
teriology, yet it is one which it is impossible to remove.
We carry it constantly with us upon our skins,
STAPHYLOCCICCrS  KPIDKRMimS
Welch has described, under the name Staphylococcus
cpidennidis alhns^ a microeoccus which seems to be habit-
ually present upon the skin, not only upon the surface,
but also deep down in the Malpighian layer. He is of
the opinion that it is the same organism which is familiar