In addition to the above-mentioned properties of milk, this food has also the great advantage of throwing the minimum amount of work upon those organs whose duties are concerned with the assimilation of food and the elimination of its waste products. We have already mentioned that animals whose thyroids have been extirpated can only survive if they are put on a milk diet. (Breisacher,[294] Blum.[295]) This shows that when the thyroid is extirpated or, what is the same thing, entirely degenerated, only milk food can be tolerated, for the poisons of other food, like meat, are normally destroyed to a great extent by the thyroid gland. Footnote 294: Breisacher: Loc. cit. Footnote 295: Blum: Loc. cit. In old age there is greater or less degeneration of the thyroid gland. Just as is the case with infants, whose thyroids are not yet developed, so also old people, as a general rule, are more helpless against poisons formed by the decomposition of meat. For such persons evidently, just as for infants, milk food is the best. Here, again, we see the similarity that exists between infancy and senility, and we realize the truth of the saying that in senility we return to childhood. That milk is the best food to keep the thyroid in good working order has been proved by the experimental researches of Fordyce.[296] Footnote 296: Fordyce: British Med. Journal, vol. x, p. 619, 1902. In our opinion one of the greatest advantages of milk as a food is that it exacts for its assimilation so little work from some of our most overworked and most important organs, like the stomach, liver, and kidneys. It is certainly a boon to an overworked stomach, which is otherwise normal, when we prescribe a diet of raw milk, which, for many persons, is more digestible than most other foods. It is a fundamental principle in the treatment of old age to give a rest to those organs of the body which are the most active. Such a rest will certainly do good to the stomach, especially in the case of heavy eaters, and will improve its vitality. The same maxim holds good for the liver and kidneys. There is no food which, with the same nutritive content, contains so few harmful toxic products as milk. Imagine the difference between the liver or thyroid of a heavy meat eater, and those of one who has long taken mainly milk. The experiments of Chalmers Watson[297] and of Forsyth[298] speak volumes on this point. Footnote 297: Chalmers Watson: Loc. cit. Footnote 298: Forsyth: Loc. cit.