PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 471 



red : eruptions of the skin, diarrhoea, croup, convulsions, water on 

 the brain, ophthalmia, &c. 



A great sympathy exists between the head and teeth. The 

 ophthalmic nerve extends to the eye. The superior maxillary com- 

 municates between the nerves of the eye, ear, and face, and the 

 great sympathetic nerve. The inferior maxillary is connected 

 with the under jaw, and runs deep, it is sub -divided and forms 

 two nerves, one passes to the tongue, and forms the sense of 

 taste, and the other to the lips and chin. 



Teeth are liable to diseases, some of which are hereditary. If 

 you find children with decayed teeth, you will discover that their 

 parents had them likewise. Some teeth are largely composed of 

 soft bone, which is porous and decays readily, external injuries, 

 tartar, calcareous particles, &c,, produce inflammation and induce 

 decay, which is readily imparted from one to another, until they 

 make an elegant gentleman appear disgusting and slovenly. A 

 woman may have the eye of a gazelle, the cheek of a rose, the 

 form of a Venus, and if her teeth are defective, they will all be 

 lost upon man. 



The whole number of teeth in a well developed mouth is thirty- 

 two, sixteen above and sixteen below. They consist of four 

 classes : Cuspids, bicuspids, incrsors and molares. 



The permanent teeth appear about the sixth year. 



1. Molares, at the age of six and a half years. 



2. Middle incisors, seven and a quarter years. 



3. Lateral incisors, seven and a half years. 



4. First bicuspides, eight and a half years, 



5. Second bicuspides, ten and a half years, 



6. Cuspids, or eye teeth, thirteen years. 



7. Second molares, fourteen and a half years, 



8. Wisdom teeth, twenty years. 



Teeth can be easily preserved as long as life lasts, if taken in 

 time, or as soon as decay commences, if they are thoroughly 

 cleansed and filled with gold, scientifically. If, however, the 

 minutest particle of decay is left in and the filling placed on top, 

 in a short time it becomes loose, as the decay continues, and the 

 filling falls out, after which it is much more difficult to accom- 

 plish the object. Still, with the mineral preparation that I am 

 about to show you, such teeth may be made to last as long as the 

 owner of them. One of the phials on the table contains a pure 

 silex and the other a liquid ; by combining these two a soft paste 



