Human body temperature to give the most accurate assessment of core body temperature, particularly in hypothermia. In the early 2000s, ingestible thermistors in capsule form were produced, allowing the temperature inside the digestive tract to be transmitted to an external receiver; one study found that these were comparable in accuracy to rectal temperature measurement. In the 19th century, most books quoted "blood heat" as 98 °F, until a study published the mean (but not the variance) of a large sample as . Subsequently that mean was widely quoted as "37 °C or 98.4 °F" until editors realised 37 °C is closer to 98.6
Temperature the system, which was described previously. Rearranging Equation 6 gives a new definition for temperature in terms of entropy and heat: For a system, where entropy "S"("E") is a function of its energy "E", the temperature "T" is given by i.e. the reciprocal of the temperature is the rate of increase of entropy with respect to energy. Statistical mechanics defines temperature based on a system's fundamental degrees of freedom. Eq.(10) is the defining relation of temperature. Eq. (9) can be derived from the principles underlying the fundamental thermodynamic relation. It is possible to extend the definition of temperature even to