darkened room will make the subject of the experiment go
into a series of convulsions.

On the chemical side, an explanation for these nervous phenomena has
been advanced. Lime in the blood and cells appears to be necessary in
a number of ways. In the making of bone and teeth, in the coagulation
of the blood, in the keeping of fluid within the blood vessels, and
in maintaining the tone of the nerves, it plays a major role. Now the
parathyroids, among all the glands of internal secretion, seem to act
as the prime regulators of the amount of lime held within the blood
and cells. For when the parathyroids have been completely and
aseptically excised, without injuring any other organ, immediately the
body begins to lose lime. Something has gone out of it that helped
it to bind lime, and without that essential something, the internal
secretion presumably of the parathyroids, the lime departs. As
a conspicuous consequence the teeth fail to develop properly,
particularly as to their enamel, for which lime is an essential
constituent. Hair is lost, there is a general wasting, the nails get
brittle, and the bones soften, and the animal dies. Supplying lime
directly, particularly by direct injection into the blood, will
relieve the symptoms.

In man, a condition of nervous over-excitability has been described
as tetany. It occurs most often in the young, the pregnant, or in
vomiting after operations. All sorts of tests have related the malady
to the phenomena succeeding parathyroid deprivation, and they are now
looked upon as aspects of it. Individuals have been reported suffering
from an insufficiency of the internal secretion of parathyroids,
with a sudden extreme depression, nervousness and restlessness, an
inability to sleep or sit still, and a tremulous handwriting. Such
reports round out the evidence for the importance of the parathyroids
in an understanding of the factors which control growth, especially
as regards lime utilization, for without lime properly handled no
building of cells is possible. Also the parathyroids are necessary to
a steadiness of muscle and nerve.

THE PANCREAS

The business of the parathyroids concerns the keeping of lime in the
body. Another gland, the pancreas or sweetbreads, this time within the
abdomen, a close neighbor of the solar plexus, alias the abdominal
brain, is occupied with holding and hoarding sugar in the body,
particularly in the liver, the great sugar warehouse. This matter