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 goes to infinity. On the empirical temperature scales, which are not referenced to absolute zero, a negative temperature is one below the zero-point of the scale used. For example, dry ice has a sublimation temperature of which is equivalent to . On the absolute Kelvin scale, however, this temperature is . On the absolute scale of thermodynamic temperature no material can have a temperature smaller than or equal to 0 K, both of which are forbidden by the third law of thermodynamics. Temperature is basically defined for a body in its own state of internal thermodynamic equilibrium, and in this