The falling out of hair, or its turning gray, after acute infectious diseases or after grief and sorrow, may have some connection with the well-known changes in the ductless glands, especially in the thyroid, in these conditions. This is made quite clear by Sajous’s demonstration that these glands collectively govern the activity of general oxidation, that is to say the vital process itself. As we have previously mentioned, a moustache or whiskers may grow in women suffering from disease of the ovaries, just as after castration or the climacteric. It is also very interesting that a premature grayness often occurs in cases of insanity, and can be attributed to the frequent changes in the thyroid and sexual glands in these conditions. The nutrition of the skin is entirely under the influence of the thyroid. After extirpation or degeneration of the thyroid, there occurs atrophy of the sebaceous and sudorific glands. In myxœdema the skin is dry and never perspires. On the contrary, in Graves’s disease, or after thyroid medication in large doses, there is abundant perspiration. Deposits of tartar are common symptoms in all forms of thyroid degeneration. Retraction of the gum follows and the teeth loosen and fall out. This is also a common symptom in diabetes, but here only in advanced cases. In such cases there is, as we[36] have shown, an exhaustion of the thyroid gland, which develops as a consequence of the previous hyperactivity of the thyroid gland in the early stages of the disease. As a rule the teeth of a diabetic only fall out in the severer form of the disease, generally after acetone has begun to show itself in the urine. Footnote 36: Lorand: “Die Entstehung der Zuckerkrankheit,” Berlin, 1903, and in French translation, Paris, 1904. Important changes take place in the subcutaneous tissue after extirpation of the thyroid gland. In such cases there is either augmentation of connective tissue or of fat. Thus, in the case of a young bull, whose history we followed, there has been an increase of thirty pounds of fat within a few months after extirpation of the thyroid. The same thing happened in the case of a young horse, whose thyroid was also extirpated. There are, however, still more facts which show the great influence of the thyroid upon the metabolism of fat. Thus we know very well that by thyroid medication we are able to reduce fat considerably. This is due to the action of the thyroid which, as shown by many authors, increases the process of oxidation. In Graves’s disease these processes are augmented. In the opposite condition (myxœdema) they are diminished. By giving thyroid extract we are able to augment, positively, the processes of oxidation in the tissues, as shown by Professor Magnus-Levy,[37] of Berlin, and many others. Footnote 37: Magnus-Lévy: “Der Stoffwechsel bei Erkrankungen einiger Drusen ohne Ausführgang,” in v. Noorden’s “Handbuch der Pathologie des Stoffwechsels”, vol. ii, Berlin, 1907.