The part played by the secretion of the supra-renal glands in the production of arterial disease has brought renewed attention to a theory which supposed that certain glandular organs in the body play a preponderating part in senile degeneration. Dr. Lorand[21] in particular has argued that “senility is a morbid process due to the degeneration of the thyroid gland and of other ductless glands which normally regulate the nutrition of the body.” It has long been noticed that persons affected with myxodema, as a result of the degeneration of the thyroid gland, look like very old people. Everyone who has seen the cretins in Savoy, Switzerland, or the Tyrol, must have noticed the aged appearance of these victims, although very often they are quite young. The condition of cretinism, with its profound bodily changes, is the result of degeneration of the thyroid gland. On the other hand, it is well known that in old people the thyroid and the suprarenals frequently show cystic degeneration. It is quite probable, therefore, that these so-called vascular glands have their share in producing senility. Many facts show that they destroy certain poisons which have entered the body, and it is easy to see that, if they have become functionless, the tissues are threatened with poisoning. It does not follow, however, that their action in producing senility is exclusive, or even preponderating. M. Weinberg, at the Pasteur Institute, made special investigations on this point, and found that the thyroid gland and the supra-renal capsules were almost invariably normal in old animals (cat, dog, horse), although the latter showed unmistakable signs of senility. Similarly in an old man of 80 years, who died from pneumonia, the thyroid gland was quite normal. It must not be forgotten that the aged very often die from infectious diseases such as pneumonia, tuberculosis, and erysipelas. In these diseases the vascular glands generally, and the thyroid gland in particular, are very often affected, with the result that what is due to infection has been set down as a symptom of old age.[22] Although the appearance of patients from whom the thyroid gland has been removed, or in whom it has degenerated spontaneously, recalls that of old people, it is possible to exaggerate the similarity. In the masterly accounts of such unfortunates, recently compiled by the well-known surgeon Kocher[23] there are many points which are characteristic, without being typical, of old people. Oedema of the skin which characterises thyroid patients is by no means usual in old age. The loss of hair, normal in the patients, is not a character of old age. In myxedematous women, menstruation is very active; it ceases in old women. The great muscular development of myxedematous patients distinguishes them from old people.