The Parathyroids are several small pea-like bodies situated close to the thyroid, and histologically resemble the undeveloped thyroid. Their removal is followed by the condition called tetany, which manifests itself by exophthalmos, rapid respiration, and painful tonic muscular spasms, most marked in the hands and feet. These symptoms may be due to a loss of ability to neutralize toxins. Relief from them has been obtained by the intravascular use of a soluble lime salt.

The secretion of the adrenals is obtained from the medullary portion which is developed from the same source as the sympathetic ganglia. It is evidently derived from the chromaffin cells, so-called on account of their affinity for the chrome salts. Wherever those cells are present the active principle can be procured, the greatest collection being in the adrenal. This secretion is evidently of marked importance, as disease of or removal of those bodies causes severe disturbances in the individual. If completely removed, collapse and death occur within a few hours. When the breaking down has taken place slowly, a condition known as Addison's disease results. In it there is an increasing weakness, accompanied by anemia, emaciation, and a peculiar bronzing of the skin and mucous membrane of the mouth.

Whether or not it has a relation to the pigmentation of the skin and to the cachexia is not settled, but it is probably the result of oxidation by the secretion.

The action of the adrenal secretion seems to be more upon the vasomotor system. When applied locally the vessels will contract, and if injected into the circulation will cause a rise in blood-pressure. This is due to the contraction of the arterioles.

The secretion of the pituitary body seems to bear definitely upon the nutrition of the tissues. When diseased the condition of acromegaly is generally present. In it there is a marked enlargement of the bones of the face and of the extremities. The enlargement is due to an actual hypertrophy of the parts involved. Accompanying this there is usually some interference with speech, and the memory is slightly affected.

In the pancreas, besides the three external secretions, there is also an internal one. It seems to be chiefly concerned in carbohydrate metabolism; it is a glycolytic ferment.