ordinary bullets, and those which our soldiers are now receiving from
German rifles. The former were often so slight that it was quite a
common occurrence for a soldier to discover accidentally that he had
been wounded some time previously. In the present war rifle wounds
have been amongst the most deadly with which we have had to deal.

It will thus be seen that in most cases the wounds were anything but
clean-cut; with very few exceptions, they were never surgically clean.
By surgically clean we mean that no bacteria are present which can
interfere with the healing of the tissues, and only those who are
familiar with surgical work can realize the importance of this condition.
Its maintenance is implied in the term "aseptic surgery," and upon this
depends the whole distinction between the surgery of the present and
the surgery of the past. Without it the great advances of modern
surgery would be entirely impossible. When we say, then, that every
wound with which we had to deal was infected with bacteria, it will be
realized how different were the problems which we had to face
compared with those of work at home. But the difference was even
more striking, for the bacteria which had infected the wounds were
not those commonly met with in England. These wounds were for the
most part received in the open country, and they were soiled by earth,
manure, fragments of cloth covered with mud. They were therefore
infected by the organisms which flourish on such soil, and not by the
far more deadly denizens of our great cities. It is true that in soil one
may meet with tetanus and other virulent bacteria, but in our
experience these were rare. Now, there is one way in which all such
infections may be defeated--by plenty of fresh air, or, better still, by
oxygen. We had some very striking proofs of this, for in several cases
the wounds were so horribly foul that it was impossible to tolerate
their presence in the wards; and in these cases we made it a practice