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 of retaining sugar and controlling its output is one of the utmost significance for growth and metabolism, the resistance to infections, the response to emergency situations, and in general to the mobilization of energy for physical and mental purposes.  For without sugar sufficiently at hand for the cells, no muscle work or nerve work, the essentials of the struggle for existence, are possible.

The pancreas is an organ with both an internal and external secretion.  The external secretion, long known, evolved by the major portion of the gland, is poured into the small intestine to play the star in digestion.  Scattered here and there among the definitely glandular cell groups creating the external secretion are smaller collections of cells, called the islets of Langerhans, which have been demonstrated to elaborate the internal secretion.  There are about a million of these islands in each gland.  The hormone has been called insuline.  Unlike most of the glands with a double secretion in which the internal is absolutely independent, and so to speak, unconscious of the external, these two of the pancreas are often disturbed together, perhaps because trouble easily hits them both together.

Quite the most well-known disease due to disturbed internal secretory function of the pancreas is diabetes.  An enormous amount of work has been spent upon the various aspects of it as a mystery.  Hundreds of papers in a dozen languages upon the subject are in existence.  In a nutshell, they have established pretty well that diabetes is a disease in which there is an excess of sugar in the blood and urine because of an insufficient amount of the secretion of the islands of Langerhans in the pancreas.  Removal of the pancreas makes the body, essentially the liver, unable to retain sugar, as well as unable to burn up sugar for energy.  The situation is comparable to a locomotive with its coal bins leaking, and the coal itself acting as if made of slate or some equally uncombustible or only partially combustible material.