Not only does the stomach render us thirsty and otherwise, and excite a
desire of warm and cold drink, but also the thoracic viscera, namely,
the heart and lungs, and likewise the liver. And drinking does not
straightway allay the desire, but a small quantity of cold drink
will rather allay the thirst than a great quantity of warm. Persons
so affected are refreshed by inhaling cold air, which has no effect
in alleviating the thirst of the stomach. Thus, also, those who are
contrariwise affected, suffer sensibly from breathing cold air; this
is the strongest mark of coldness of the lungs; but they also hawk up
phlegm, and expectorate it with coughing. Dryness of the lungs is marked
by freedom from excrementitious discharges and from phlegm; and humidity,
by being excrementitious, and rendering the voice dull and hoarse; and
the recrementitious discharge is also very great when they attempt to
speak in a louder or sharper tone.
* * * * *
COMMENTARY. The ancients were of opinion, that the lungs are an
accessory organ, made to administer to the heart. “It is the heart,”
says Aretæus, “which imparts to the lungs the desire of drawing in
cold air.” And in like manner, Theophilus holds that the other organs
of respiration were made for the sake of the heart, in order that its
innate heat may be cooled, increased, and nourished. (De Fabrica Hominis,
p. 89, ed. Greenhill.) The physiologists differed respecting the uses
of respiration. Thus, according to Galen, the famous Asclepiades held
that it is for the generation of the soul itself, breath and life being
thus considered to be identical; Philistion, Diocles, and Aristotle,
for the ventilation of the innate heat; Hippocrates for its nutrition
and refrigeration; and Erasistratus for the filling of the arteries
with spirits. All these opinions are discussed and commented upon by
Galen, who determines the purposes of respiration to be twofold: first,
to preserve the animal heat; and second, to evacuate the fuliginous
portion of the blood. He was aware of the analogy between respiration
and combustion, and comes to the conclusion that they are processes of a
similar nature: he accordingly compares the lungs to a lamp, the heart to
its wick, the blood to the oil, and the animal heat to the flame. (Galen,
de usu Respir.) Aristotle gives the name of pneuma to the vital heat of
animals, and ascribes the source and maintenance of it to the double
functions of respiration and digestion. (De Pneumate.) See further, Third
Book, s. 27.
The following extract from Alexander Aphrodisiensis will explain
the opinions entertained by physicians and _savans_ of a later age:
“Wherefore there is a natural tepidity, the same I mean as the innate
heat, whence springs the origin of the animal, its nature; for it is
congenital with the animal, and therefore is called natural, being in the
main the instrument of the soul’s powers.” (De Feb. viii.)
The following extract from Haly will show that the opinions of the
Arabians on this subject did not differ from those of their Grecian
masters, and more especially of Galen: “Respiration is necessary, for the
sake of the heart, which is the fountain, and, as it were, the focus of
vital heat, whence it is diffused over the rest of the body. It requires
some aerial substance to ventilate the heat and ebullition of the heart,
and in order to evacuate the fuliginous vapours which are found in it.”
(Theor. iii.)