viii Preface 



The first volume consists of two comprehensive articles dealing with the 

 physiology of populations. Calhoun's "The Social Use of Space" presents 

 many interesting new ideas on the behavior of animals in populations and 

 the effects of grouping of individuals upon the physiology of the organism. 

 Where many workers have thought of the experimental animal only as an 

 individual apparently divorced from his environment and other members 

 of the species, Calhoun points out the fallacy of this view in providing 

 experimental data that demonstrate the effects of numbers of individuals 

 on the behavior of each individual. Christian's article on population growth 

 treats the problem largely from an ecological viewpoint in dealing with 

 limiting factors of natural populations and population interrelationships. 



Volume II will consist of three contributions dealing with natural 

 populations and their adaptations to stressful environments. Dr. Charles 

 Kayser treats the mammalian phenomenon of hibernation as a mechanism 

 for avoiding periods of unfavorable environment, and Dr. Robert Chew 

 deals with water balance in desert rodents. Inasmuch as reproduction is 

 considerably affected by the environment, it too can be considered a process 

 modified by environmental stresses, and is discussed in the second volume. 

 Subsequent volumes will include articles on such topics as temperature and 

 metabolism, physiological genetics, photoperiod, and orientation by echo- 

 location. The Editors will conclude the series with a summary article on 

 the phylogeny of physiology. 



The Editors feel particularly fortunate in that they have received fine 

 cooperation from outstanding authorities in the specific subject matter 

 topics covered. It is the caliber of the individual author on which these 

 volumes base their contribution to science; and while the Editors assume 

 any responsibility for defects of organization or inadvertent errors, the 

 credit for the success of the volumes, as a whole, rests on the indi^'idual 

 contributors. 



October, 1963 William V. Mayer 



Richard G. Van Gelder 



