nts upon animals are only permitted under
direct license from the Government, and then only within premises
specially licensed for the purpose. In England this license is in the
grant of the Home Secretary, and confers the permission to experiment
upon animals under general anaesthesia, provided that after the
experiment is completed the animal must be destroyed before regaining
consciousness. If it is intended to carry out simple hypodermic
inoculations and superficial venesections, Certificate A, granting this
specific permission and dispensing with the necessity for general
anaesthesia must be obtained _in addition to the license_; whilst if the
inoculation entails more extensive operative procedures, and it is
necessary to observe the subsequent course of the infection, should such
occur, the license must be _coupled with Certificate B_--since this
certificate removes the compulsion to destroy the animal whilst under
the anaesthetic. Further special certificates and combinations of
certificates are required if cats, dogs, horses, asses or cattle are to
be the subjects of experiment. Under every certificate it is expressly
stipulated that if the animal shows signs of pain it must be destroyed
immediately.

The animals generally employed in the study of the pathogenic properties
of the various micro-organisms are:

_Cold Blooded._ _Warm Blooded._ _Hot Blooded._
Frog. Mouse. Fowl.
Toad. Rat. Pigeon.
Lizard. Guinea pig.
Rabbit.
Monkey.

~Preparation.~--Before inoculation, the experimental animals should be
carefully examined, to avoid the risk of employing such as are already
diseased: since it must be remembered that in a state of nature, as well
as in captivity, the animals employed for laboratory inoculations are
subject to infection by various animal and vegetable parasites, and in
some instances such infection presents no symptoms which are obvious to
the casual examination; the sex should be noted, the weight recorded,
and the rectal temperature taken. The remaining items of importance are
the time of the inoculation, the material that is inoculated, and the
method of inoculation, and finally under what authority the experiment
is performed. In the author's laboratory these data are entered upon a
pink card which forms part of a