The example we have cited suffices to show how much care one took at that time in the preparation of substances destined to be used in the preservation of the teeth, and demonstrates at the same time that Fauchard, inventor of that and many other preparations, besides being an able surgeon-dentist, was also exceedingly well versed in dental materia medica. Chapter VII treats of the general causes of dental, alveolar, and gingival diseases, and contains the complete enumeration of these maladies. The causes of dental affections may be of two orders, viz., internal (general diseases, dyscrasic conditions) and external (the action of heat and cold, mechanical causes, etc.). After having spoken in particular of various causes, Fauchard adds: “Little or no care as to the cleanliness of the teeth is ordinarily the cause of all the maladies that destroy them.” The author divides maladies of the dental apparatus into three classes, that is: 1. Maladies deriving from external causes and acting, therefore, especially on the crown or uncovered part of the tooth. 2. Maladies of the hidden parts of the tooth, that is, of the neck and root. 3. Symptomatic maladies, deriving from the teeth. In the first class the author includes 45 pathological states, 17 in the second and 41 in the third, making up a total of 103 morbid conditions. This should be sufficient to give us an idea of the accuracy with which Fauchard studied the maladies of the dental apparatus, especially if one considers that preceding authors had reduced these maladies to a very small number. Fauchard’s classification is very complete, for notwithstanding the progress made in succeeding years in this science, the pathological conditions not to be found comprised in it are exceedingly few. Naturally, the 103 diseases enumerated by Fauchard do not represent as many distinct morbid entities. The author, in classifying dental maladies, keeps especially in view the requirements of the practitioner, and therefore makes numerous distinctions in each morbid process. Thus, he distinguishes a great many varieties of caries, viz., the soft and putrid caries, the dry caries, the caries in part dry and in part soft, the caries complicated by fracture, the superficial caries, the deeper and the deepest, the caries of the different surfaces of the crown, and so on. Also in the classification of other morbid processes, Fauchard makes multifarious distinctions. The passage referring to worms in the teeth deserves to be here reproduced:[414]