184 PATHOGENIC BACTERIA.

to us under the name of Staphylococcus pyogenes albus,
but in an attenuated condition. If his opinion be correct,
and we have seated deeply in our derm a coccus which
can at times cause abscess-formation, the conclusions of
Robb and Ghriskey, that sutures of catgut when tightly
drawn may be a cause of skin-abscesses by predisposing
to the development of this organism, are certainly justi-
fiable.

Not only does the coccus occur in the attenuated form
described, but we have very commonly present upon the
skin, generally as a harmless saprophyte, the important
Staphylococcus pyogenes albus, which is a common cause
of suppuration.

STAPHYLOCOCCUS PYOGENES ALBUS.

Although, as stated, the Staphylococcus pyogenes albus
is a common cause of suppuration, it rarely occurs alone,
the studies of Passet showing that in but 4 out of 33 cases
which he investigated was this coccus found by itself.
When pure cultures of the coccus are injected subcu-
taneously into rabbits and guinea-pigs, abscesses some-
times result; sometimes there is no result Injected
into the circulation of these animals, the staphylococci
sometimes cause septicemia, and after death can be found
in the capillaries, especially of the kidneys. From these
illustrations it will be seen that the organism is feebly
pathogenic.

In its vegetative characteristics the Staphylococcus
albus is almost identical with the species next to be de-
scribed, but differs from it in that there is no golden color
produced. Upon the culture-media it grows white.

STAPHYLOCOCCUS PYOGENES AUREUS.
Generally present upon the skin, though in smaller
numbers, is the dangerous and highly virulent Staphylo-
coccus pyogenes aureus (Fig. 50), or " golden Staphylococ-
cus'1 of Rosenbach. As the morphology of this organ-
ism, and indeed the generality of its characters, are