o be much
in the open air, and often inspiring more deeply than is common in
older persons. Also, if the carbon of the food does not have a
requisite supply of oxygen from the air, or other sources, the body
becomes emaciated, although nourishing food may be used. And on the
other hand, if there be a diminished supply of food, but an abundance
of atmospheric air, leanness and emaciation are sure to follow; owing
to the fact that if the oxygen has no waste carbon from the body to
unite with, it combines with the fat, and some other soft portions of
the body, which the Author of nature seems to have provided for this
very purpose; as is seen in the case of hibernating animals, who enter
their places of winter abode sleek and fat, but crawl out in the
spring not merely deprived of their fatty matter, but also with great
diminution of all the softer parts, which have given up their share of
carbon to supply animal heat. One important cause of emaciation in
febrile diseases is the greater rapidity of the pulse and respiration,
which consume more carbon than is afforded by the scanty supply of
food that is taken, although profuse perspiration, which almost always
occurs in some stages of fevers, greatly diminishes the full state of
the body.

K.

The theory of Baron Liebig concerning the change which the blood
experiences in color, in its passage through the lungs, meets with
the approbation of many physiologists, although there are some
important difficulties in the way of fully receiving it. A chemical
analysis of the blood shows it to be composed of albumen and
fibrin, together with some other substances, in small proportions, and
always perceptible traces of iron. He attributes the change in color
to the iron, as this substance enters into combination with carbon
and oxygen. For, as the blood passes through the trunks of the larger
vessels and capillaries, it receives the carbon from the tissues
which are continually transformed, and taking up the oxygen from the
arterialized blood, forms carbonic acid, which unites with the iron,
forming proto-carbonate of iron. This being of a gray color, he
supposes it to be that which, with the other impurities of the blood,
gives the venous blood the dark blue color. Then, as the blood
comes in contact with the oxygen, as it is returned and exposed to
this element in the lungs, the carbonic acid leaves the iron, which
has a stronger affinity for oxygen than for carbonic acid, an