I know it has been said, by some physicians--and by those who are sensible men, in other respects, too--that the child's stomach is a pretty correct guide in regard to quantity. If we give it too much, say they, it will reject it;--as if that were an end of the matter. But it is not so. It is by no means harmless to fill the child's stomach as full as is possible without overflowing. Such a process, though it should not create disease directly, would produce a gluttonous habit. The stomach, being muscular, may be increased in size by use, like all other muscular organs. The hands, the arms, the legs, the feet, the fleshy portions of the face, even, may be disproportionally enlarged by constant use. Thus a sailor, who uses his hands and arms much more than his legs and feet, has the former unusually large; one who is much accustomed to walking, has large feet; and in a tailor, who from childhood uses his lower limbs comparatively little, they are both small and slender. On the same principle, the stomach, by inordinate use, and by carrying unreasonable loads, may be made nearly twice as large as nature intended, and may demand twice as much food. And I have no doubt that the bulk of mankind, young and old, eat about twice as much as nature, unperverted, would require. If the suggestions of our last section are duly attended to, one of the causes which lead the stomach to demand an unreasonable quantity of food will be avoided--I mean the too frequent "repetition of aliment." And if we never depart from the general rule, already laid down, not to give the infant anything but its mother's milk, we shall escape the evils incident to variety. SEC. 5. _How long should milk be the only food._ On this point, there is a great diversity of opinion. Perhaps the most approved role, of universal application, is, that the first change should be made in the child's diet, when the teeth begin to appear. This period, it is well known, cannot be fixed to any particular age, but varies from the fifth to the twelfth month. Some mothers, who have borne with me patiently to this place, will probably here object. "What child," they will ask, "would ever have any strength, brought up so?" Not only a little pap and gruel is, in their estimation, necessary, long before this period, but even many choice bits of meat. Now I am very sure, that these choice bits--whatever they may be--given to a child before it has teeth, not only do no good, but actually do mischief. Indeed, that which does no good in the stomach must do harm, of course; since it is not only in the way, but acts like a foreign body there, producing more or less of irritation.