eat, by producing an internal rise of temperature, may thus
cause all the phenomena of fever. Of these phenomena the most prominent
is disturbance of the nervous system and of the circulation. In order to
determine whether the heat itself directly causes the nervous
disturbance, or whether it produces it indirectly by causing changes in
the blood, I applied caloric directly to the brains of animals. This was
done by fitting a hog's bladder like a bonnet over the head and allowing
hot water to run through it. It was found that stupor, coma,
convulsions, and finally death from arrest of the respiration, were
produced, sometimes gradually, sometimes suddenly, precisely as in the
case of exposure of the animal in a hot chamber. Moreover, on opening
the skull and plunging a thermometer into the cerebrum immediately after
death or the supervention of unconsciousness, it was found that these
phenomena were developed at the same brain-temperature when the heat was
locally applied as when the animal was exposed in the hot box. Thus, if
any given species in the hot box became unconscious when the temperature
reached 110 deg. Fahrenheit, this species also became unconscious when the
locally-heated brain attained a temperature of 110 deg.; or if death
occurred by arrest of the respiration in the hot box at 114 deg., so did it
when the locally-heated brain reached that point.

Dr. Lauder Brunton of England has performed a series of experiments upon
the circulation parallel to those just narrated. Anaesthetizing animals
and exposing the heart, he has found that the action of that organ is
accelerated and weakened by the local application of heat, precisely as
occurs in fever.

In order to test the effect of the withdrawal of heat, I have taken a
rabbit out of the hot chamber, in which it lay upon its side totally
unconscious, and plunged it into a bucket of cold water. The temperature
of the water rose rapidly, whilst that of the rabbit fell even more
rapidly. As soon as the bodily heat approached its normal intensity
consciousness returned, and in a few moments the animal, which had just
before been at the point of death, was running about the grass.

Some months since I had an opportunity of repeating this experiment upon
a human being.

In acute inflammatory rheumatism it sometimes happens that the swelling
and pain of the joints suddenly disappear, and the patient becomes
comatose or wildly delirious. It has been customary to