In one milliliter of human saliva, 100 million bacteria exist. More than 600 species of bacteria live in the human mouth, and half of these have yet to be identified. This month, the International Journal of Systematic and Evolutionary Microbiology reported that a new species has been identified. It was named Prevotella hiticola. This particular bacteria was found in both healthy and cancerous tissue, and it is associated with many oral diseases, as well as infections throughout the body. Scientists hope that discovering Prevotella histolica is a step toward finding better ways to fight tooth decay and gum disease, the two leading bacterial diseases for humans.