"Tin is used in the form of little balls, or tubes, but folds are better; introduce the metal gradually, taking care to pack it so that it will bear equally upon all points; the folds superimpose themselves one upon the other; thus we obtain a successive stratification much more exact and dense, and it is impossible there can be any void." ("Theory and Practice of Dental Surgery," J. Lefoulon, Paris, 1844.) CHAPTER III. "Besides gold, the only material which can be used with any hope of permanent success is tin foil. Some dentists call it _silver_, and a tooth which cannot be filled with it cannot be filled with anything else so as to stop decay and make it last very long. It can be used only in the back teeth, as its dark color renders it unsuitable for those in front. When the general health is good, and the teeth little predisposed to decay, this metal will preserve them as effectually perhaps as gold; but where the fluids of the mouth are much disordered it oxidizes rapidly, and instead of preserving the teeth rather increases their tendency to decay." (Dr. Robert Arthur, Baltimore, 1845, "A Popular Treatise on the Diseases of the Teeth.") The false idea that a patient must have good health, normal oral fluids, and teeth little predisposed to decay, or else if filled with tin the decay would be hastened, originated with a German or English author, and has been handed down in works published since early in 1800. It even crept into American text-books as late as 1860, the authors of which now disbelieve it. "Tin undergoes but little change in the mouth, and may be used with comparative safety." ("Surgical, Mechanical, and Medical Treatment of the Teeth," James Robinson, London, 1846.) "Tin is soft, and can be easily and compactly introduced, but it is more easily acted on by the secretions of the mouth than gold and is less durable, but in the mouth of a healthy person _it will last for years_. Still, inasmuch as it cannot be depended on in _all_ cases, we are of the opinion that it should _never_ be employed." ("The Human Teeth," James Fox, London, 1846.) The italics are ours. Every metal has a limited sphere of usefulness, and it should not be expected that tin will contend single-handed against all the complicated conditions which caries presents. "Of all the cheaper materials, I consider tin the best by far, and regard its use fully justifiable in deciduous teeth and in large cavities, as it is not every man who can afford the expense of nine leaves of gold and four hours of labor by a dentist on a single tooth." (Dr. Edward Taylor, _Dental Register of the West_, 1847.) "I consider tin good for any cavity in a chalky tooth: it will save them better than anything else." (Dr. Holmes, 1848.)