itself by the falling out and poor growth of hair. Insufficiency of
iron in the blood is evidenced, apart from lack of spirit, by paleness
of face and blue lips; insufficient sodium by glandular tumors and
abnormal cartilaginous growths.

The entire amount of iron in the blood of an adult person is, on the
average under normal conditions, four grams, as much as a nickel weighs.
We may well judge that this amount is not sufficient to set the motive
power of our bodies in action, if we overlook that complex factor the
circulation of blood. The left side of the heart has the capacity of
containing about six ounces of blood, and every heart beat drives this
amount through the aorta. With seventy beats to the minute, twenty-five
pounds of blood is pumped from the heart every minute. What is the
result? That the four grams of iron keep up such an incessant movement
that they pass from the heart into the aorta sixty times an hour or 1440
times in 24 hours. It may be asserted, therefore, that in 24 hours 13
pounds of iron (that is 1440x4 grams) pass from the heart into the
aorta. Can it be doubted, in view of this, that the iron serves to
produce an electro-dynamic force?

In respect to the generation of electricity, it matters not whether
there be an entirely new supply of iron passing a given point, or
whether the same iron pass that point anew each minute. Two factors work
together in the circulation of the blood, namely, the active attraction
of nerve tissue and the passive susceptibility of the blood contents to
that attraction. Faraday has conclusively shown that blood is magnetic
in character because of the iron it contains. If four grams of iron is
the normal quantity in the blood, it is clear that the reduction of this
amount, say by two grams, will lessen its susceptibility and slacken its
circulation. The electrical nerve ends will then strain in vain for the