It is undeniable that the ideas expressed by Fauchard on the pathogeny of caries, cannot hold good against criticism. Nevertheless, we owe a great deal to this author for having once for all put an end to the ridiculous theory of dental worms, and for having tried to find a reasonable explanation of the manner in which caries is produced. The teeth, says Fauchard, have not all the same disposition toward this morbid process; indeed, notable differences are to be observed in this respect. The molars are, in fact, more apt to become decayed than the incisors or the canines; and the upper incisors and canines are more subject to this disease than the inferior ones, because, by reason of their position, they are more frequently uncovered and more exposed to heat and cold, whether in eating and drinking or whether in the mere aspiration or expiration of the air. It is to be observed, besides, that when the eruption of the last molars is considerably delayed they easily decay.[418] Having very frequently observed the symmetrical decay of corresponding teeth on both sides of the same jaw, Fauchard considers that these cases are not simply accidental, but rather holds that the fact depends on a special cause, which, however, is not easy to determine. He offers, at any rate, a sufficiently good explanation when he says that as certain morbid causes (bad humors, etc.) must affect both sides of the mouth identically, it is but natural that the effects of such causes should be altogether analogous on the right and on the left, and manifest themselves symmetrically on teeth having the same configuration, the same structure, and the same consistence. Before speaking of the treatment of caries,[419] Fauchard alludes to the fallaciousness of the many remedies against toothache which were largely sold at his time by charlatans and impostors of every kind. “Some pretend to cure toothache with an elixir or some special essence; others with plasters; others by means of prayers and signing with the cross; others with specifics for killing the worms that are supposed to gnaw the tooth and so cause pain; others pretend to be so clever that they can cure the most inveterate toothache by merely touching the tooth with a finger dipped into or washed with some rare and mysterious liquid; others finally promise to cure every kind of toothache by scarifying the ears with the lancet or cauterizing them with a red-hot iron.”