INTRODUCTION XIH 



I 



together the key advances in theory and observations referred to in the 

 preceding paragraphs. Second, it demonstrated the usefulness of both 

 temperature and pressure in basic biological research. And third, it em- 

 phasized the importance of relationships between temperature and other 

 factors, such as hydrostatic pressure, in seeking to understand fully the 

 influence of any one of these factors. 



The usefulness of both temperature and pressure in theoretical biology, 

 and the importance of inter-relationships between the effects of tempera- 

 ture, pressure and the chemical environment or state of biological systems 

 are again emphasized by the papers in this volume, especially those on 

 muscular contraction, cell division and nerve activity. Brown's paper on 

 muscle, for example, elucidates certain aspects of muscular contraction 

 in a measure that could scarcely have been achieved through any other 

 approach, and at the same time provides a basis for understanding the 

 specific differences in muscle physiology among organisms temporarily 

 accustomed or genetically limited to different habitats. For, the same basic 

 system, through relatively simple changes in the chemical environment, 

 assumes different optimum temperatures, different optimum pressures and 

 different over-all energies of activation. 



Now, where do we stand at the moment, and what is the outlook for 

 future research on the biological effects of temperature? 



Recently, for the first time in approximately a generation, two books^' - 

 dealing extensively with biological temperature relations have been in- 

 dependently published. The present volume presents, in more detail than 

 could be treated in either of the other two books, both new data and re- 

 views on representative problems of general interest to biology. These 

 three new books evidence a renewed and promising interest in the subject. 

 Some questions have been answered, at least in part, while others seem 

 well along the way toward solution, and still others are clearly more re- 

 mote of solution. Divers new practical, as well as theoretical, problems 

 have come to the fore, such as those pertaining to life in arctic and tropical 

 environments, the action of fluctuating temperatures in preventing injury 

 to both plants and insects, the influence of sudden temperature changes in 

 synchronizing cell division, the relative temperature-insensitivity of 'bio- 

 logical clocks', etc. At the same time, new knowledge and improved means 

 of investigating molecular structure are available, the kinetic complexities 

 of rapid reactions and sequences of reaction are being resolved, and much 

 more is known now then heretofore concerning the pathways and cata- 

 lysts of intermediary metabolism. Thus it is reasonable to believe that we 

 stand on the threshold of major new advances through research with 

 temperature and the factors which modify its influence on biological 

 systems. 



