Page 21 - skinner

\1 Of the Tartar and Septic Acid. The Tartar confifts of three different fpecies, viz. the yellow, the black, and the green. The two former are nearly fimilar in their confiftence and ef fects : the latter is chemically denominated the fep- tic acid. The tartar is generated from particles of the aliments, vlfcid exhalations from the ftomach, and a foft mucous matter formed from a combination of the food and faliva ; thefe fubftances collecting and remaining on the teeth, foon produce putreffcence. This putreScent matter, (like every thing terreftriai) foon undergoes a change. The animal fluids, collect ing in cavities, ftagnate and depofit an abforbent ean!-. ; and thus form ftony concretions. The juices of the mouth, and the fubftances beforementioned, are pecu liarly calculated to produce this adventitious concre tions upon the teeth. This ftony matter generally be gins to form upon the necks of the teeth, near the gum, a fituation infinitely more liable to produce mifchievous effects, than any other external part of the tooth. The enamel, near the neck of the teeth, is extremely thin, and eafily acled upon by the perni cious effects of this deftruclive fubftance. The gums likewife, now fuffer from the baneful effccls of the tartar, which is continually accumulating, and which foon deftroys their firmnefs and adhefion to the neck of the teeth. The gums now difeafed, exhibit a rough edge, of a livid colour ; and foon after f sellings, ex- creffences and ulcers ; continually difcharging pus ; which at this ftage of the difeafe, ceafes only with the total expulfion of the teeth contiguous to the parts af fected. The green tartar (or feptic acid,) is materially different from the yellow and black, both in its appear ance and effects upon the teeth : this fubftance never forms a concretion. Itfirft appearslike a green ftain up on that part of the teeth next the gum, where the enamel is very thin, gradually encreafing (unlefs checked bv C