There are few persons who brush the teeth properly. I will tell you the right way. First of all procure a tooth-brush of the best make, and of rather hard bristles, to enable it to penetrate into all the nooks and corners of the teeth: then, having put a small quantity of warm water into your mouth, letting the principal of it escape into the basin, dip your brush in warm water, and if you are about using Castile soap, rub the brush on a cake of the soap, and then well brush your teeth, first upward and then downward, then from side to side—from right to left and from left to right—then the backs of the teeth, then apply the brush to the tops of the crowns of the teeth both of the upper and of the lower jaw,—so that _every_ part of each tooth, including the gums, may in turn be well cleansed, and be well brushed. Be not afraid of using the brush: a good brushing and dressing will do the teeth and the gums an immensity of good; it will make the breath sweet, and will preserve the teeth sound and good. After using the brush the mouth must, of course, be well rinsed out with warm water. The finest set of teeth I ever saw in my life belonged to a middle-aged gentleman; the teeth had neither spot not blemish—they were like beautiful pearls. He never had toothache in his life, and did not know what toothache meant! He brushed his teeth, every morning, with soap and water, in the manner I have previously recommended. I can only say to you—go and do likewise! Camphor ought never to be used as an ingredient of tooth-powder, it makes the teeth brittle. Camphor certainly has the effect of making the teeth, for a time, look very white; but it is an evanescent beauty. Tartar is apt to accumulate between and around the teeth; it is better in such a case _not_ to remove it by scaling instruments, but to adopt the plan recommended by Dr. Richardson, namely, to well brush the teeth with pure vinegar and water. PREVENTION OF DISEASE, ETC. 351. _If a boy or a girl show great precocity of intellect, is any organ likely to become affected?_ A greater quantity of arterial blood is sent to the brain of those who are prematurely talented, and hence it becomes more than ordinarily developed. Such advantages are not unmixed with danger; this same arterial blood may excite and feed inflammation, and either convulsions, or water on the brain, or insanity, or, at last, idiocy may follow. How proud a mother is in having a precocious child! How little is she aware that precocity is frequently an indication of disease! 352. _How can danger in such a case be warded off?_