The question now arises, by what means can we ascertain whether the ductless glands are in good condition or not? We will now try to answer this important question. We can diagnose a healthy condition of the ductless glands either directly, by the examination of those glands which are available for a digital examination, as the thyroid, sexual glands or liver, or indirectly, by the examination of the state of those functions which are governed by these glands; e.g., the heart’s action, the pulse, regulation of temperature, defæcation, diuresis, digestion, activity of the skin and its glands, condition of the nervous system, etc. Before entering upon the examination of these glands we must first ascertain whether our patient comes of a long-lived stock, or, if not, whether diseases that are particularly harmful to the ductless gland, and are commonly hereditary, like tuberculosis and syphilis, have occurred in the family. According to our observation boys more frequently look like their mothers, and girls like their fathers, and also inherit their qualities. After having ascertained the family history, we must inquire whether the patient has had any diseases that are specially harmful to the ductless glands: e.g., infectious diseases—scarlet fever, diphtheria, typhoid, etc.—and also ascertain his usual diet and habits, keeping in mind the bad effects of abundant meat food upon the thyroid, as well as of certain stimulants like alcohol and tobacco. As these, if of bad quality and taken in quantity for a long time, have the most damaging influence on the ductless glands, our prognosis of a long life will be duly influenced, and in particular unfavorably for those who come of a short-lived stock, or who have been weakened by previous infectious diseases. If some persons, otherwise healthy and of good family history, can with impunity indulge till old age in wine and tobacco, yet this is not a general rule. Individuals are known who drank and smoked till over one hundred years of age, but such cases are rare, and we may quote the Latin proverb: “Quod licet Jovi, non licet bovi.” Everybody will admit that the expectation of life in those who are moderate in the use of wine and tobacco and also, let us insist, of tea and coffee, is much greater than in the immoderate. We will further deal with this question in our chapters on alcohol and tobacco. After having given an exhaustive history of the persons whose probable lifetime we are trying to determine, we next proceed to the examination of those ductless glands which are available for direct examination, and first of all, the thyroid.