514 Jo\irnal of Comparative Neurology and Psychology. 



ing a stage of development which will justify its recognition by 

 the most timid, narrow, or prejudiced naturalist as an increas- 

 ingly exact natural science. Sciences differ widely in degree 

 of exactitude ; at present, for example, the biological sciences 

 are far less exact than the physical, but one may reasonably 

 argue that this is due to inherent difficulties in dealing with the 

 materials rather than to the impossibility of applying exact 

 methods. Psychology as a natural science, or rather psychology 

 in so far as it is considered as a natural science, is in its infancy. 

 As physiology gradually approaches the standard which physics 

 has set for it, so psychology approaches, and will the more 

 rapidly approach as those in allied fields recognize its progress, 

 this same standard. 



For those of us who have at heart the establishment and 

 advancement of comparative psychology as a science coordinate 

 with physiology there is the clear duty to make our work emi- 

 nently worthy of scientific recognition and reliance. Casting philo- 

 sophical implications aside, so far as our scientific work is in ques- 

 tion, we should apply ourselves to the study of psychic reactions 

 with intent to place our knowledge of them on a level with or 

 above that of the non-psychic as represented by the condition 

 of present day physiology. In attempting to do this we should 

 ever be willing and eager to take advantage of the assistance 

 which the closely allied biological and less directly related phys- 

 ical sciences can give us. Speculative sciences have their 

 place, but we shall accomplish most for the science of psychic 

 reactions if we keep our metaphysical longings in the back- 

 ground and strive ceaselessly for accurate and complete descrip- 

 tions of the reactions with which we are concerned — reactions 

 which are the most complex and interesting of biological phe- 

 nomena. ROBERT M. YERKES. 



