Книга только для ознакомления
. The mouth, however, does not actually concoct the
food, but merely facilitates concoction; for the subdivision of the
food into small bits facilitates the action of heat upon it. After the
mouth come the upper and the lower abdominal cavities, and here it
is that concoction is effected by the aid of natural heat. Again, just
as there is a channel for the admission of the unconcocted food into
the stomach, namely the mouth, and in some animals the so-called
oesophagus, which is continuous with the mouth and reaches to the
stomach, so must there also be other and more numerous channels by
which the concocted food or nutriment shall pass out of the stomach
and intestines into the body at large, and to which these cavities
shall serve as a kind of manger. For plants get their food from the
earth by means of their roots; and this food is already elaborated
when taken in, which is the reason why plants produce no excrement,
the earth and its heat serving them in the stead of a stomach. But
animals, with scarcely an exception, and conspicuously all such as are
capable of locomotion, are provided with a stomachal sac, which is
as it were an internal substitute for the earth. They must therefore
have some instrument which shall correspond to the roots of plants,
with which they may absorb their food from this sac, so that the
proper end of the successive stages of concoction may at last be
attained
|
