Thus the thyroid can be of valuable aid for the prevention of old age, and for deferring its onset as long as possible; and for this purpose it will be necessary to begin our treatment in women at about the age of 35, or in certain cases, such as where many pregnancies have occurred, even before this age, and in men at some time after 40 (see also Chapter LIII). Still, to avoid abuses in the use of this efficient drug, it would be necessary to pass a law prohibiting its sale without a medical prescription. Besides the thyroid gland, the extracts of the sexual glands can also be used; thus, ovarian extracts for women, and testicular extracts for men. We have also witnessed good results with ovarian and testicular extracts of pigs. Long before ourselves, Brown-Séquard and Professor von Poehl and many others made very interesting observations on testicular extract, on which we shall dwell in the chapter on the treatment with testicular extracts. Besides the above extracts, those of the kidneys and of the pancreas have also given us, and others, very good results, and they can be used with advantage in the prevention and rational treatment of old age in combination with the other extracts, though preferably in cases where the functions of these organs are deficient. In old age that has already become manifest they should always be used, as they will facilitate the work of these very important organs, and thus prolong their vitality. In this manner an old man will be able to employ these organic extracts of the pig to work for the benefit of his own organs, or, at any rate, to assist in their work. We have given above a sketch of the dangers that follow us from the cradle until old age, and hasten its arrival, and shown by what means we can avoid or diminish them in the different stages of life; we would now like to offer a few hints that may prove useful for any of these periods in life. We have shown in the previous chapters that the degeneration of certain glands with internal secretions, especially the thyroid, liver, and kidneys, will produce a condition of auto-intoxication, as poisonous products will not be destroyed in the proper manner, and also not eliminated from the body. Therefore our whole energy must be turned to working in time against this auto-intoxication of the body. This can be most rationally done by a careful hygiene of these different ductless glands—into which we will enter later in separate chapters—and also by special cultivation of the functional efficiency of those organs that eliminate poisonous products from the body, such as the kidneys, intestines, and the skin.