278

PATHOGENIC BACTERIA.

FIG. 76.—Tetanus bottle.

a couple of inches long. Connected with this glass
tube, by means of a short piece of rubber tubing, is

the bulb of a broken pipette,
the other end of which is
plugged with cotton (Fig. 76).
When the steam sterilization
takes place the expanding fluid
ascends to the reservoir repre-
sented by the pipette bulb, de-
scending again as the fluid cools.
When the sterilization is com-
pleted the reservoir is detached,
the inoculation made by passing
a very fine pipette into the bottle,
the projecting glass tube drawn
out to a fine tube, and the bottle
stood in hot water until the ex-
panding fluid ascends to the apex
of the pointed glass tube. The
tube is now sealed in a flame and the bottle and its con-
tents allowed to cool. In cooling the retracting fluid
leaves a vacuum which at once draws up any minute
bubbles of air remaining, and allows the tetanus bacillus
to grow in a condition of very fair anaerobiosis.

Tetanus bacilli exist in nature as widely distributed
saprophytes. They are quite common in the soil, and
the fact that they are most plentiful in manured ground
has suggested that they originate in the intestines of
horses and reach the earth from their excrement. Le
Dentu has, however, shown that the tetanus bacillus is
a common organism in New Hebrides, where there are no
horses. In these islands the natives poison their arrows
by dipping them into a clay rich in tetanus bacteria.

The work of Kitasato has given us a very exact
knowledge of the tetanus bacillus and completely estab-
lishes its specific nature.

The organisms generally enter the animal body through
a wound caused by some implement which has been in