It is also quite unnecessary for us to expose ourselves to the dangers arising from the decomposition of meat, which is particularly injurious, when taken in large quantities, to the thyroid, as shown by the experiments of Breisacher, Blum, Chalmers Watson, etc., more especially if animal food be taken that is not quite fresh and can cause the formation of ptomaines. According to Blum the thyroid has the special function of destroying poisons formed in the intestines, in particular by the decomposition of animal food. Now when too much work is thrown up on this important gland, it is easy to understand that after a time it will give out, and to prevent this we must avoid taking large quantities of animal food or fish (which is meat also, a fact not realized by many people), and when we do take it, we must first be certain that it is in a fresh condition. To enable us to do this we are provided with special sense-organs, and our eyes, nose, and the taste papillæ of our tongue will inform us whether the meat, and especially the fish or crustacean, is in a fit condition to be eaten. We have mentioned several times that alcohol and tobacco, taken in large quantities or for a long time, are deleterious to the thyroid, which fact will justify our abstinence therefrom, or the greatest moderation in their employment; those who can do without stimulants will always be the best off. Sexual excesses can also be easily avoided, and women who wish to retain their youth will do well not to expose themselves to pregnancies year after year after having had three or four children. It is, however, great good fortune to have a numerous progeny, and by careful hygiene, as plenty of instances prove, the struggle against premature old age can be carried out successfully. In regard to this we may refer to the chapters on the causes of old age and on sexual hygiene. Diseases of the ovaries must be particularly avoided, as all changes in those glands will react on the thyroid, which is closely related to them. Doubtless one of the most difficult tasks will be the avoidance of strong emotions: grief and sorrow; and yet we are not helpless against them, as will be illustrated in the chapter on the hygiene of the mind and on the advantages of a religious belief. Having dwelt on the necessity of preventing injury to this important gland, we will now show that there are certain means of enhancing its vitality,—which effect we can obtain by improving the circulation, and removing agencies by which this would be impaired. As Sir Herman Weber has shown, it is possible to improve the working condition of this gland by massage, which should be done daily and is readily carried out.