ic material, and acquires
an ethereal spirit, which is dissipated in fibrous motion._ II. _The
placenta is a pulmonary organ like the gills of fish. Oxygenation of
the blood from air, from water, by lungs, by gills, by the placenta;
necessity of this oxygenation to quadrupeds, to fish, to the foetus in
utero. Placental vessels inserted into the arteries of the mother. Use
of cotyledons in cows. Why quadrupeds have not sanguiferous lochia.
Oxygenation of the chick in the egg, of feeds._ III. _The liquor amnii
is not excrementitious. It is nutritious. It is found in the esophagus
and stomach, and forms the meconium. Monstrous births without heads.
Question of Dr. Harvey._

I. From the recent discoveries of many ingenious philosophers it appears,
that during respiration the blood imbibes the vital part of the air, called
oxygene, through the membranes of the lungs; and that hence respiration may
be aptly compared to a slow combustion. As in combustion the oxygene of the
atmosphere unites with some phlogistic or inflammable body, and forms an
acid (as in the production of vitriolic acid from sulphur, or carbonic acid
from charcoal,) giving out at the same time a quantity of the matter of
heat; so in respiration the oxygene of the air unites with the phlogistic
part of the blood, and probably produces phosphoric or animal acid,
changing the colour of the blood from a dark to a bright red; and probably
some of the matter of heat is at the same time given out according to the
theory of Dr. Crawford. But as the evolution of heat attends almost all
chemical combinations, it is probable, that it also attends the secretions
of the various fluids from the blood; and that the constant combinations or
productions of new fluids by means of the glands constitute the more
general source of animal heat; this seems evinced by the universal
evolution of the matter of heat in the blush of shame or of anger; in which
at the same time an increased secretion of the perspirable matter occurs;
and the partial evolution of it from topical inflammations, as in gout or
rheumatism, in which there is a secretion of new blood-vessels.

Some medical philosophers have ascribed the heat of animal bodies to the
friction of the particles of the blood against the sides of the vessels.
But no perceptible heat has ever been produced by the agitation of water,
or oil, or quicksilver, or other fluids; except those fluids h