bstracted by the cold water. Loud and long
continued speaking, the crying of infants, moist air, all exert a
decided and appreciable influence on the amount of food which is
taken.

We have assumed that carbon and hydrogen especially, by combining
with oxygen, serve to produce animal heat. In fact, observation
proves that the hydrogen of the food plays a no less important part
than the carbon.

The whole process of respiration appears most clearly developed,
when we consider the state of a man, or other animal, totally
deprived of food.

The first effect of starvation is the disappearance of fat, and this
fat cannot be traced either in the urine or in the scanty faeces.
Its carbon and hydrogen have been given off through the skin and
lungs in the form of oxidised products; it is obvious that they have
served to support respiration.

In the case of a starving man, 32 1/2 oz. of oxygen enter the system
daily, and are given out again in combination with a part of his
body. Currie mentions the case of an individual who was unable to
swallow, and whose body lost 100 lbs. in weight during a month; and,
according to Martell (Trans. Linn. Soc., vol. xi. p.411), a fat pig,
overwhelmed in a slip of earth, lived 160 days without food, and was
found to have diminished in weight, in that time, more than 120 lbs.
The whole history of hybernating animals, and the well-established
facts of the periodical accumulation, in various animals, of fat,
which, at other periods, entirely disappears, prove that the oxygen,
in the respiratory process, consumes, without exception, all such
substances as are capable of entering into combination with it. It
combines with whatever is presented to it; and the deficiency of
hydrogen is the only reason why carbonic acid is the chief product;
for, at the temperature of the body, the affinity of hydrogen for
oxygen far surpasses that of carbon for the same element.

We know, in fact, that the graminivora expire a volume of carbonic
acid equal to that of the oxygen inspired, while the carnivora, the
only class of animals whose food contains fat, inspire more oxygen
than is equal in volume to the carbonic acid expired. Exact
experiments have shown, that in many cases only half the volume of
oxygen is expired in the form of carbonic acid. These observations
cannot be gainsaid, and are far more convincing than those arbitrary
and artificially produced phenomena, sometimes called experiments;
experimen