The author of this chapter has been invited to revise the literature on the general physiological aspects of the action of temperature for the 20 years which have elapsed since the publication of the first edition of his relevant book (1). Well over 3,000 papers in this field have been published since then, and only a small fraction can be mentioned here. These should be regarded as a representative sample illustrating the general trends prevailing during this period. The two most important are (a) a descriptive study of the temperature response, requirements, and tolerance of various physiological properties and functions, and (b) an attempt to obtain a closer insight into the intimate cellular chemomechanisms by analytic studies of the responses of living systems to temperature variations.
THERMIC PROPERTIESThe effect of body size upon the time required to attain equilibrium with the external temperature has been illustrated by experiments on the fruit fly (Drosophila), where 30 secs. suffice to stabilize the wing rhythm at a new temperature (2), and on bacteria in which flash-heat exposures of 0.5 sec. duration were applied, when only 10-5 sec. were lost in heat conduc tion (3; cf. also 164). The combined effect of body size, coloration, radiation, and air current in medium-sized insects was studied, and the results show that the excess temperature varies with from 0.4 to 1.0 power of the body size, compared with 0.4 to 0.7 power in control experiments with spherical plasticine models (4). As regards poikilothermic animals in general, several good reviews are available (see S, 6, 7, 18).The specific heat of the sickle-shaped human erythrocyte was found to be normal, so the condition cannot therefore be attributed to abnormal crystallization of haemoglobin. On the other hand, the specific heat of normal red cells decreases somewhat on slight heating (8).
RATE PROCESSESTemperature coefficients.-To describe the extent of the response to temperature variations of physiological rate processes, three kinds of temperature coefficient mainly are used, namely, Q10, J.I. (otherwise written as E, or A), and b [in the b, a-rule (cf. 1)]. Most authors apply these constants merely as a means of description without accepting the theoretical implica-1 The survey of the literature pertaining to this review was completed in May, 1956. 59 Annu. Rev. Physiol. 1957.19:59-82. Downloaded from www.annualreviews.org by Case Western Reserve University on 11/02/14. For personal use only. Quick links to online content Further ANNUAL REVIEWS
B E LEHR A DEKtions attached to anyone of them ; for this purpose QID is still most widely used despite its recognized drawbacks, as it is the easiest to calculate. The somewhat more complicated b, a-rule, calculating the temperature from a specific zero point (a) upwards and using the log/log representation, has been recently applied by various authors to the reproduction rate of ciliates (9, 10); to the rate 0f respiration in bacteria (11, 12), sliced mammalian tissue (13), and insects (14); to the ...