Don't forget to brush your tongue (gently) every day, advises toothpaste-maker Warner-Lambert Co. The tongue harbors up to four times as many bacteria as the teeth . . . Looking for a few bald men: Washington Hospital Center's Department of Dermatology needs 30 male volunteers for a six-month test of viprostol, a synthetic hormone with some promise as a hair-growing agent. Volunteers must be between 18 and 55, in good health. For more information, call 541-7586 . . . Salaries of hospital and health care employes rose 5.6 percent last year, the smallest increase in nine years, reports The Wyatt Co., a consulting firm. Highest increases went to staff physicians (7.2 percent) and administrative staff (5.9 percent); lowest to dietary personnel (4.6 percent) . . . About 180,000 Americans a day are treated in hospital emergency rooms, up from 120,000 five years ago, reports a study for Emergency Medicine and Cardiovascular Medicine magazines. Reasons: Emergency facilities are better equipped and better staffed than ever, and many patients go directly to the E.R., even for non-emergencies . . . Carnation Co. is awaiting FDA approval for the first birth control food -- for dogs. It contains the hormone mibolerone and would cost about three cents a can more than regular Carnation dog food.