INTRODUCTION XI 



available that, under appropriate conditions, the thermal denaturation of 

 proteins is quantitatively reversible on cooling; in consequence, there was 

 no reason to believe that reversible protein denaturation played a key 

 role in some of the important effects of temperature or, as we now know, 

 of pressure as well. Thus it is understandable that Belehradek's ^-ompre- 

 hensive, detailed book on temperature and life processes, published in 

 1935,- contained no reference to pressure, and Cattell's thorough review 

 of the physiological effects of pressure, published in 1936, contained 

 scarcely more than a passing reference to temperature. 



It was about this time, however, that the stumbling blocks referred to 

 above were removed through coincidental advances whose significance in 

 the over-all picture was not immediately realized. The contribution of most 

 general importance was Eyring's theory of absolute reaction rates which, 

 in 1935, became possible through advances in quantum physics and other 

 fields bearing on chemical kinetics. This theory provided a rational basis 

 for the interpretation of the relation between chemical reaction rates and 

 pressure as well as temperature. In the same and preceding year, Brown 

 presented data that clearly indicated a fundamental relationship between 

 the influence of temperature and pressure on muscular contraction. In 

 addition, his data indicated that a similar relationship among different 

 organisms accustomed to different environmental temperatures was cor- 

 related with their specific ranges in temperature for physiological activity. 

 Finally, by 1935, the research chiefly of Anson, Mirsky, Northrop and 

 Kunitz on enzymes and other proteins established that thermal denatura- 

 tions can be reversed, in part or in full according to the conditions of the 

 experiment, and the suggestion had been made (Anson and Mirsky, 1931 ) 

 that such reactions might be involved in controlling physiological activi- 

 ties. A few years later these independent advances were brought together 

 and consolidated in studies of bacterial luminescence. 



Experiments on bacterial luminescence by Brown, Johnson and Mars- 

 land in 1941-42 revealed some basic similarities in the effects of tempera- 

 ture and pressure on muscular contraction and on luminescence intensity, 

 respectively. A new relationship was also observed, viz. between hydro- 

 static pressure and the action of narcotics; at the normal "optimum tem- 

 perature" of luminescence, the inhibitory effect of alcohol, urethane or 

 certain other agents disappeared under increased pressure. In collaboration 

 with Eyring and his associates, a quantitative hypothesis was worked 



■ A recent book, Temperatur und Leben, by Precht, Christopherson and Hensel 

 (Springer, Berlin, 1955) includes an extensive compilation of the literature on bio- 

 logical temperature relations since Belehradek's monograph, and includes some ref- 

 erence to pressure also. 



