Some of them, it is true, such as the prohibition of uncooked or partially cooked meat, are confirmed by modern knowledge. But the greater number of the Mosaic rules, as, for instance, the prohibition of the consumption as food of blood or the flesh of pigs or hares, and so forth, are in direct opposition to a modern knowledge of hygienic diet.
Metchnikoff, being a scientist, uses, of course, these reports of longevity gathered from historians and travelers merely as suggesting profitable lines of research, not as proof of any theory. Such proof can only be obtained by direct experimentation, and accordingly he has for the past fifteen years been experimenting upon himself. The Pasteur people do not belong to that class of physicians who refuse to take their own medicine. Metchnikoff still has a weak heart as the result of an intentional inoculation with recurrent fever, and some of his collaborators have inoculated themselves with the most loathsome of diseases for the purpose of testing a remedy for it. Brown-Séquard, of the Collège de France, tried, at the age of seventy-two, to rejuvenate himself by injections of animal secretions, but his hopes proved unfounded.
But the means advocated by Metchnikoff for the prevention of senescence, even though it may never fulfill his expectations, has at least the merit of being harmless, for it is merely the systematic employment of a food which has been in use by a large part of the human race from the earliest times. The object being to colonize the lactic bacilli in the lower part of the digestive tract, the best way of attaining this has yet to be worked out. The generous drinking of buttermilk or curdled milk, though this may be nutritious or otherwise beneficial, does not necessarily accomplish the object, for the bacilli may have been mostly killed off by the acidity or may be destroyed in the stomach. Taking a dose of the bacilli in a dried form, as a tablet or powder, may fail to serve the purpose, because they are in an inactive state and may not be able to secure a foot-hold for lack of suitable food, such as milk or fruit sugar. So Metchnikoff has adopted the plan of taking pure cultures of the Bulgarian and paralactic bacilli in pasteurized milk or sweetened bouillon and also in the jam and in a kind of candy prepared from cooked dates soaked in the pure cultures. He abstains from all alcoholic beverages and uses only cooked food and boiled water. His daily diet in addition to this consists of three to five ounces of meat, grains, legumes, and stewed fruit.[3]