The tongue, like the rest of the inner surface of the mouth, may have several diseases common to the inner mouth cavity. However, its refinements in touching and tasting bring it in contact with all substances entering the mouth and expose it to more irritation than the rest of the oral cavity.

Tongue Discoloration. A gray tongue discoloration, coated on the tongue with a map-like appearance, is often called “geographic tongue” and is of little significance. This condition is known to persist at times for years without any disease being

Fig. 26. Geographic tongue-a clearly demarcated discoloration of the tongue surface, arriving and departing without an exactly known cause. It is sometimes thought due to body metabolism and sometimes to external pigmentation as from excessive smoking.

present. It ordinarily disappears in a short time without any treatment and may well represent a temporary gastric upset.
Brownish-yellow Tongue Discoloration has two usual meanings. The first is the over-use of tobacco in which the tongue is stained with nicotine and tar to produce brownish stain on its surface. The stain will disappear shortly after the use of tobacco is stopped.

The second possible meaning of a brownish-yellow tongue may mean pernicious anemia. When the possibility of tobacco staining is not present, and the patient is fifty years of age or over, the lemon-yellow tongue may have serious meaning, and should be seen by the physician.

Bluish Discoloration on the tongue is usually a type of birthmark. It is usually painless, does not bleed and is not sore, is

Fig. 27. Blood vessel tumors (angiomas) usually exist since birth as birthmarks. Soft bluish masses, they are usually painless and rarely cancerous.

slightly elevated and occasionally covered with small amounts of hair. They have great nuisance value but little actual danger. They, of course, exist from childhood.

Fiery Red Coloration of the tongue, usually means glossitis, or an irritated tongue. Glossitis can be quite painful and appears to have no apparent cause. It is however, frequently due to a deficiency of vitamins, particularly vitamin B12, and frequently improves when this vitamin is given. The condition is thought by some physicians to be a pre-cancerous condition and worthy of careful observation.