The Relation between Heat Production,
Oxygen Consumption and Temperature in Some
Poikilotherms
J. N. R. GRAINGER
With 2 Figures
Abstract
A calorimeter is described which is suitable for measuring the heat production
of aquatic poikilotherms. The relation between the rates of oxygen consumption
and heat production is given for bakers yeast between 20° and 35°. 1 ml oxygen
was equivalent to 2.6 to 4.9 calories with glucose as substrate. Similar equivalences are given for AJellus, Nuce!!a, Limnaea, Lumbricu!us and Rana tadpoles.
LAVOISIER in 1780 was the first to measure the amount of heat produced
by an animal; RUBNER [5] was the first to show that the heat calculated from
metabolism was very close to that which could be measured directly in a
calorimeter. Much direct and indirect calorimetry [1, 2] has since been carried out on man and domestic animals. Little has however been done on
poikilotherms [3]. A programme has been started in this Department on
the energetic efficiency of poikilotherms at different temperatures. This
paper is concerned with one aspect of this, namely the relation between the
rate of oxygen consumption and the rate of heat production.
Methods: The calorimeter used in the heat measurements consisted of a Dewar
flask of 230 ml capacity closed by a rubber bung. Three glass tubes projected
through the bung. One of these carried the leads to a nichrome heating coil,
another carried leads to two glass-covered thermistors (F 23, Stantel) and the
third was connected to a small glass pipette for bubbling oxygen or nitrogen
through the flask contents. The thermistors were connected to the circuit shown
in Fig. 1. To ensure adequate electrical insulation the thermistor probes projected
from a small rubber bung attached to a glass tube, inside which lay the junctions
between the thermistors and their leads, and which was joined by rubber tubing
to one of the three glass tubes projecting through the flask bung. This tube contained some silica gel.
In most experiments 50 ml of medium was used in the flask. The flask was
totally immersed in a constant temperature tank controlled to ± 0.02° by a mercury
toluene regulator with proportioning head. It was found necessary to immerse
the fixed resistor (C) in a tube in the constant temperature tank. At temperatures
of 30° and higher (C) was replaced by a 1 kohm resistor. Heat flow between the
flask contents and the bath was measured in a series of calibration experiments by
observing the rise (or fall) of temperature in the flask for various temperature
Oxygen Consumption and Temperature in Some
Poikilotherms
J. N. R. GRAINGER
With 2 Figures
Abstract
A calorimeter is described which is suitable for measuring the heat production
of aquatic poikilotherms. The relation between the rates of oxygen consumption
and heat production is given for bakers yeast between 20° and 35°. 1 ml oxygen
was equivalent to 2.6 to 4.9 calories with glucose as substrate. Similar equivalences are given for AJellus, Nuce!!a, Limnaea, Lumbricu!us and Rana tadpoles.
LAVOISIER in 1780 was the first to measure the amount of heat produced
by an animal; RUBNER [5] was the first to show that the heat calculated from
metabolism was very close to that which could be measured directly in a
calorimeter. Much direct and indirect calorimetry [1, 2] has since been carried out on man and domestic animals. Little has however been done on
poikilotherms [3]. A programme has been started in this Department on
the energetic efficiency of poikilotherms at different temperatures. This
paper is concerned with one aspect of this, namely the relation between the
rate of oxygen consumption and the rate of heat production.
Methods: The calorimeter used in the heat measurements consisted of a Dewar
flask of 230 ml capacity closed by a rubber bung. Three glass tubes projected
through the bung. One of these carried the leads to a nichrome heating coil,
another carried leads to two glass-covered thermistors (F 23, Stantel) and the
third was connected to a small glass pipette for bubbling oxygen or nitrogen
through the flask contents. The thermistors were connected to the circuit shown
in Fig. 1. To ensure adequate electrical insulation the thermistor probes projected
from a small rubber bung attached to a glass tube, inside which lay the junctions
between the thermistors and their leads, and which was joined by rubber tubing
to one of the three glass tubes projecting through the flask bung. This tube contained some silica gel.
In most experiments 50 ml of medium was used in the flask. The flask was
totally immersed in a constant temperature tank controlled to ± 0.02° by a mercury
toluene regulator with proportioning head. It was found necessary to immerse
the fixed resistor (C) in a tube in the constant temperature tank. At temperatures
of 30° and higher (C) was replaced by a 1 kohm resistor. Heat flow between the
flask contents and the bath was measured in a series of calibration experiments by
observing the rise (or fall) of temperature in the flask for various temperature