mechanical cleansing effect. The wide tube of the vagina is further
protected by a normal bacterial flora which produces conditions
hostile to other and pathogenic bacteria. The most common infections
are the sexual diseases, which are due to organisms which find
favorable conditions for growth in and on the surface and which are
conveyed from a similar surface by sexual contact.

It remains a question whether bacteria can penetrate an intact surface
producing no injury at the point of entrance and be carried by the
lymph or blood into internal organs where they produce disease.
Internal infections are often found with seemingly intact body
surfaces, but it is impossible to exclude the presence of minute or
microscopic surface injuries by which the organisms may have entered.
It is also possible that a slight injury at the point of entrance may
heal so completely as to leave no trace.

The chief danger from wounds is that their surfaces may become
infected. Death from wounds is due more frequently to infection than
to the actual injury represented by the wounds. Much depends upon the
character of the wound. Infection of clean wounds which are made by a
sharp cutting instrument and from which there is abundant hæmorrhage
with sealing of the edges of the wound by clotted blood, rarely
happens. Typical wounds of this sort are often made in shaving, and
infection of such wounds is extraordinarily rare. If, with the wound,
pathogenic organisms are placed in the tissue, or foreign substances
such as bits of clothing are carried in with a bullet, for example, or
if the instrument causing the wound be of such a character as to
produce extensive lacerations of tissue, infection is more apt to
occur. The less frequency of infection in modern wars is in part due
to the simpler character of the wounds and in part to the fact that