with the surgeon speaking of them, or with the location of the
disease, are now known to be due to the invasion of the wound by
microscopic plants. These bacteria, after entering the blood current
at the wound, multiply with such prodigious rapidity that the whole
system gives evidence of their existence. Suppuration of wounds is
undoubtedly due to these organisms, as is tubercular disease, whether
of surgical or medical character. Tetanus, erysipelas, and many other
surgical conditions have been almost proved to be the result of
infection by similar microscopic plants, which, though acting in the
same way, have various forms and life histories.

A distinction must be made between the "yeast plants," one of which
produces thrush, and the "mould plants," the existence of which, as
parasites in the skin, gives rise to certain cutaneous diseases. These
two classes of germs are foreign to the present topic, which is
surgery; and I shall, therefore, confine my remarks to that group of
vegetable parasites to which the term bacteria has been given. These
are the micro-organisms whose actions and methods of growth
particularly concern the surgeon. The individual plants are so minute
that it takes in the neighborhood of ten or fifteen hundred of them
grouped together to cover a spot as large as a full stop or period
used in punctuating an ordinary newspaper. This rough estimate applies
to the globular and the egg-shaped bacteria, to which is given the
name "coccus" (plural, cocci). The cane or rod shaped bacteria are
rather larger plants. Fifteen hundred of these placed end to end would
reach across the head of a pin. Because of the resemblance of these
latter to a walking stick they have been termed bacillus (plural,
bacilli).

The bacteria most interesting to the surgeon belong to the cocci and