In Bulgaria where Yogurt is a staple article of food, there are more centenarians, and more vigorous old people to be found than anywhere else on earth. Not only are the Bulgarians and the Hungarians the longest lived races in Europe, but they show a remarkable freedom from appendicitis, colitis, and other diseases due to intestinal infections, circumstances which called the attention of European physicians to a study of the milk ferment which produced Yogurt, and led to the scientific investigations, first by Masson of Geneva and later and more completely by Metchnikoff and Kellogg, which have placed its use both as a curative and a preventive agent upon a thoroughly scientific basis. Its use is bound to supersede that of kumyss, kephir, matzoon, and other lactic acid ferments on account of the fact that these ferments are able to live only in the small intestine, while Yogurt bacillus thrives in the colon, where it may be found weeks after the administration of Yogurt has ceased. The importance of this fact will be seen at once when it is recalled that the colon is the chief seat of the anaerobic infection and poison production which are the causes of intestinal autointoxication. Thus the last word of modern science on this subject would seem after all to be but the confirmation of a means for reaching natural old age which has been known for hundreds of years. But to-day we are learning to use means for the prolongation of life by the light of knowledge; no longer blunderingly, handicapped by evil habits which nullify the value of the small fraction of hygienic truth which we possess. To-day, Hygeia, while it holds out to our lips an elixir of life, insists that if it is to have its maximum power, we must also breathe rightly, sleep rightly, and eat and drink rightly. VI SOME IMPORTANT FOOD FACTS The importance of avoiding constipation will be obvious to those who have followed this account of the process of autointoxication; one should see that his daily bill of fare contains a generous supply of laxative foodstuffs, such as sweet fruits, ripe figs and prunes, acid fruits and fruits juices, fresh vegetables, fats and all grain preparations. It is of the utmost importance that the bowels should move regularly once a day. There is another reason for eating food in the shape of fruits or salads, which is that the body may have a sufficient supply of mineral salts.