250 INITIATIVE IN EVOLUTION 



character, when lying awake at night and being puzzled by a curious 

 rhythmical scratching sound coming from my next door neighbour's 

 back yard. It might have been taken by a wakeful person for 

 some mechanical work on the part of a burglar, but after listening 

 repeatedly to the apparently familiar sound I found that it came 

 from the kennel of a fox terrier kept by my neighbour. 



Purposes of Reflexes. 



All reflexes being purposive this particular innate reflex is 

 acknowledged to have for its purpose the grooming or cleaning of 

 the skin over its hereditary territory. This introduces its con- 

 nection with initiative here propounded, and the justification for 

 its introduction is contained in Professor Sherrington's statement 

 that " In the analysis of the animal's life as a machine in action 

 there can be split off from its total behaviour fractional pieces 

 which may be treated conveniently, though artificially, apart, 

 and among these are the reflexes we have been attempting to 

 decipher " — scratch -reflexes and others. There seems to be no 

 reason for the existence and stereotyped character of this reflex 

 except the need or rather the desire (if one may use a convenient 

 but inaccurate term) on the part of the dog to remove an irritant 

 which disturbs its comfort when at rest. Some " minor horrors," 

 probably fleas moving across the skin-receptive field of its shoulder 

 and back, must be assumed to be the irritant in question. This 

 touches the great question of the initiative of this remarkable 

 reflex, which seems more fixed and powerful in the dog as we know 

 him than that other reflex which leads him to turn tail and flee 

 immediately he sees a boy stoop down as if to pick up a stone. 

 I dare say a clever advocate on the opposite side might impress a 

 jury by building up a case under which an adaptation to a protective 

 need would be conceived as responsible for the rapid flight at the 

 sight of the threatening attitude of the boy. Such a reconstruction 

 is not required, for it is perfectly clear that in the history of the 

 domesticated dog the selection of such an adapted reflex could have 

 no place. The survival-value of this reflex would be nil, for the 

 number of dogs killed by a stone or maimed for life would be so 

 negligible that the production of a specialised reflex for the purpose 

 by selection or survival of the fittest would not arise. Obviously 

 the danger would be intermittent and rare ; and dead dogs tell 

 no tales. On the other hand it would be highly unpleasant for 

 dogs to be hit by stones and educability would lead them to avoid 

 the stooping attitude associated with missiles. 



