722 
DEPARTMENT OE SURGERY. 
Staphylococcus pyogenes aureus is the most common of all 
the pus-cocci, and is found flourishing on the skin of man and 
animals, under the finger nails, in the dust of rooms and in pus 
both internal and superficial lesions. It is the common 
organism of acute abscess. 
. Staphylococcus pyogenes albus is also a parasite of the 
skin of man and animals and in abscesses it is usually 
associated with the golden variety. Its pathogenicity is some- 
what less than the aureus. 
Staphylococcus pyogenes citreus is less virulent and not 
so widely diffused as the two former, but fresh cultures injected 
subcutaneously will produce an abscess from which new cultures 
can be obtained. 
Micrococcus pyogenes tenius is rather an innocent organism 
as it produces only a local suppurative process with inflammation 
ot a mild type. 
Streptococcus pyogenes is- the coccus of erysipelas, but it is 
also one of the pus-cocci. It is found in the mucous membranes 
t ieskin,the secretions and the excretions of man and animals, and 
as it does not multiply outside the body it is a parasite in the 
iu 1 sense of the term. In disease it develops chiefly in the 
submucous and subcutaneous tissues, but it may also be found 
m suppurating foci. It is not so dangerous to the lower animals 
as to man. The former seems to resist erysipelas to a marked 
degree. 
Bacilluspyocyaneus is the bacillus of green pus and does not 
greatly concern the veterinarian. 
Bacillus pyogenes foetidus, micrococcus tetragenus, tvphoid 
bacillus, diplococcus pneumonge, also belong to this category 
but the reader must refer to text books on bacterioloo-y for ^a 
more elaborate description of these as well as of those brieflv 
discussed above. 
Wound infection refers to the invasion of vegetable parasites 
into a trauma and might nicely be divided for our purpose into 
typical infection and atypical infection . 
. ( a ) typical infection, may then be used to refer to the inva¬ 
sion of particular organisms which always produce their typical 
esion, such as the bacillus of Nicolaier, bacillus tuberculosis, 
streptococcus pyogenes, staphylococcus pyogenes aureus, etc. 
(b) Atypical infection is the usual wound infection produced 
by a variety of organisms capable of producing septic processes 
e -g-> bacilli of putrefaction, a mixed infection of anyof the 
above mentioned, and a host of other cocci and bacilli w 7 hich 
