No more mother's hand on the flush child's forehead. Now, there's a thermometer that can be swallowed.

Based on remote-sensing technology developed by the National Aeronautics and Space Administration and a $75,000 grant, Dr. Russ Eberhart of Johns Hopkins University Applied Physics Laboratory in Laurel led a research group that miniaturized and encapsulized the electronics, sensors and batteries of the tiny thermometer. The device is 3/4-inch long and 1/3-inch in diameter.

Once swallowed or implanted as a suppository, the tiny pellet emits a signal that can be picked up by a receiver, providing a reading of core body temperature accurate to 0.01 degree Centigrade. The capsule eventually is excreted from the body.

The thermometer -- probably the first of a generation of remote sensors, including those to measure stomach acids, intestinal motility and electrical activity of the heart and gastrointestinal tract -- can be used for research, to study minuscule changes in temperature in different body regions and how core body temperature changes during the day, or it can be used to help treat victims of hyper- or hypothermia.

A $150 version of the thermometer for animal use will be reusable. The device for human use, estimated to cost $60 to $75 and yet to receive Food and Drug Administation approval, is not expected to be reusable.