ection is chronic, both general
and special observations should be carried out at weekly intervals. If
the animal appears to be still unaffected, it should be killed with
chloroform vapour at the end of two or three months and a complete
post-mortem carried out.

A. The ~general observations~ should take cognisance of:

1. _General appearance._ The experimental animal should be inspected
daily, not only with a view to detecting symptoms due to the
experimental infection, but also to prevent any intercurrent infection,
naturally acquired, from escaping notice (_vide_ page 337).

2. _The weight_ of the inoculated animal should be observed and recorded
each day during the course of an experimental infection at precisely the
same hour, preferably just before the morning feed.

3. _The temperature_ should similarly be recorded daily, if not more
frequently, during the whole period the animal is under observation, and
carefully charted--individual variations will at once become apparent.
It should be borne in mind that the temperature regarded as normal for
man (37.5 deg. C.) is not the normal average temperature of any of the
lower animals save the rat and mouse. The accompanying table of normal
averages for the animals usually employed in bacteriological research
may be of use in preventing the erroneous assumption that pyrexia is
present in an animal, which merely shows its own normal temperature.

NORMAL AVERAGES.
----------------------------------------------------
| Rectal | Pulse. | Respirations.
Animal. | Temp. |------------------------
| deg. C. | Rate per minute.
----------------------------------------------------
| | |
Frog | 8.9-17.2 | 80 | 12
Mouse | 37.4 | 120 | ...
Rat | 37.5 | ... | 210
Guinea pig | 38.6 | 150 | 80
Rabbit | 38.7 | 135 | 55
Cat | 38.7 | 130 | 24
Dog | 38.6 | 95 | 15
Goat | 40.0 | 75 | 16
Ox | 38.8 | 45 | ..
Horse | 37.9 | 38 | 11
Monkey (Rhesus) | 38.4 | 100 | 19
Pigeon | 40.9 | 136 | 30
Fowl | 41.6 | 140 | 12
| | |
----------------------------------------------------

B. ~Spec