t larger,
to that used for the mouse.

[Illustration: FIG. 168.--Mouse jar.]

[Illustration: FIG. 169.--Tripod.]

A layer of sawdust at the bottom of the jar absorbs any moisture and
cotton-wool or paper shavings should be provided for bedding. The food
should consist of bran and oats with an occasional feed of
bread-and-milk sop.

The use of a metal tripod, on the platform of which are soldered two
small cups for the reception of the food, inside the cage, prevents
waste of food or its contamination with excreta (Fig. 169).

After use the jars and tripods are sterilised either by chemical
reagents or by autoclaving.

The _rabbit_ and the _guinea-pig_ are confined in cages of suitable
size, made entirely of metal (Fig. 170). The sides and top and bottom
are of woven wire work; beneath the cage is a movable metal tray filled
with sawdust, for the reception of the excreta. The cage as a whole is
raised from the ground on short legs. The sides, etc., are generally
hinged so that the cage packs up flat, for convenience of storing and
also of sterilising.

The ordinary rat cage, a rectangular wire-work box, 30 cm. from front to
back, 20 cm. wide, and 14 cm. high, makes an excellent cage for
guinea-pigs if fitted with a shallow zinc tray, 35 cm. by 24 cm., for it
to stand upon.

[Illustration: FIG. 170.--Metal rabbit rage.]

A plentiful supply of straw should be provided for bedding and the food
should consist of fresh vegetables, cabbage leaves, carrot and turnip
tops and the like for the morning meal and broken animal biscuits for
the evening meal. Occasionally a little water may be placed in the cage
in an earthenware dish.

The tray which receives the dejecta should be cleaned out and supplied
with fresh sawdust each day, and the soiled sawdust, remains of food,
etc., should be cremated.

These cages are sterilised after use either by autoclaving or spraying
with formalin.

As ~animal inoculation~ is purely a surgical operation, the necessary
instruments will be similar to those employed by the surgeon, and, like
them, must be sterile. In the performance of the inoculation strict
attention must be paid to asepsis, and suitable precautions adopted to
guard against accidental contamination of the material to be introduced
into the animal. In addition, the hands of the operator should be
carefully disinfected.

The list of apparatus used in animal inoculations given below comprises
practically everything n