62	PA THOGENIC BACTERIA.
were forced. My own investigations have shown viru-
lent staphylococci of suppuration upon the conjunctive
in health. " It is very improbable that the bacteria habit-
ually present upon the skin, and ready to enter the least
abrasion, can penetrate the outer coverings of the body,
except when disease or accident -has rendered them
abnormally thin or macerated.
Turro seems to have shown that the gonococcus can
enter the tissues without any pre-existing lesion, for he
asserts that if a virulent culture simply be touched to
the meattis urinarius, the disease will be established.
 (d)	Wounds.—The results of the entrance of bacteria
into unprotected wounds are now so  familiar that no
one deserving of the name of surgeon dares to allow a
wound to go undressed.
 (e)	The Placenta.—Very frequently the occurrence of
specific  diseases during pregnancy causes  abortion   of
the 'product of conception.    In certain cases the specific
contagion passes through the placenta and infects the
fetus.    This has been pretty clearly demonstrated  for
variola, malaria, syphilis, measles, anthrax, symptomatic
anthrax, glanders, relapsing fever, typhoid, and in rare
cases for tuberculosis.
Anche found streptococci and staphylococci in the tis-
sues of aborted fceti in cases of variola.1 Except in the
case of wounds, it must be observed that, although the
bacteria are in the body—i. e., respiratory, digestive, or
sexual apparatus, etc.—they are still not in the blood, and
really not in, but only upon the surfaces of the tissues.
For their actual entrance into the circulation, Kruse2
gives the following possible modes:
 1.	Passive entrance of the bacteria through the sto-
tnata of the vessels where the pressure of the inflammatory
exudate is greater than the intravascular pressure.
 2.	Entrance of the bacteria into the vessel in the body
of leucocytes that have incorporated them.
1	La Semaine Med., 1892, No. 61.
2	Fliigge's Mikroorganismen.