AGf~ICULTURAL RESEARCH, PUSA.

188 PRACTICAL BACTERIOLOGY
the tail in the other. In this manner the animal is
held in a fixed position while the needle is introduced
under the skin near the root of the tail. Amounts up
to 1 c.c. may be injected.
Intraperitoneal inomdation may be carried out if
the animal is similarly held and thcn turned over.
For steadiness, the assistant's arms should rest on the
table. The injection is made to one side of the middle
line in the lower half of the abdomen and amounts up
to 2 c.c. can be introduced.
Intrapcritoneal inoculation may also be done without
an assistant. The animal is held at the nape of
the neck with thc left hand, and kept extended by
holding the tail with the right hand. The left hand
is turned over so that the mouse lies on its back in
. the upturncd palm. The tail is then fixed by the
little finger of the left hand. The mouse is now
firmly held, and the right hand is free to pick up the
syringe and make the injection.
Intravenous inoculation may be made into a vein
at the root of the tail if a fine needle be used and
the vein dilated by placing the tail of the animal in
warm water.
r\ small cylindrical eage made of perforated zinc, anrl j list
large enough to hold the mouse with its tail prott'llrling, is
useful for this procedure.
Intracerebral IlIoculation.-The skin over the head is depiloted
(vide p. 184) under slight ether anlCsthesia. The animal
" is completely anresthetised for the inoculation and the depilated
area sterilised with iodine-spirito A fine-bore needle
attached to a 1 c.c. syringe (as used for intradermal inoculation
-vide p. 185) is employed and easily penetrates the skull.
The site of injection is just postcrior and lateral to the vertex
and the point of the needle is cm°ried through the skull for
fl in. to :t in. Approximately 0'05 C.c. of fluid can bc injected
with safcty.
AUTOPSY
All experimental animals, whatever the causc of
death, should he examined post-mortem as a routine.
When a virulent organism such as the bacillus of
plague or of anthrax has been used, especial care must