252 INITIATIVE IN EVOLUTION 



manner be referable to selection, but, whether the suggestion be 

 valid or not, it is almost impossible to suppose that a saddle-shaped 

 area of the kind described could be under the guidance of selection. 

 The law of Parcimony forbids. There is a close similarity between 

 this saddle-shaped area in the dog and that on the cow's trunk 

 described in Chapter X. It is difficult to believe that from man 

 downwards to grasshoppers relief from mild irritating causes such 

 as this is not enjoyable to the particular animal, and yet indifferent 

 altogether as to its survival in the struggles of life for food and mates. 

 The " scalptor-reflex " only reaches the limits of the receptive 

 field of the scratch -reflex and it is contrary to observed facts that 

 parasites confine their depredations just to the region where the 

 formidable scalptor-reflex can reach. The wicked flea knows better 

 than that. The initiative of this reflex can well be pictured as 

 taking place in domesticated dogs and their wild ancestors whose 

 habitats in prehistoric times were probably infested with these 

 irritants to such a degree that no modern mind can conceive, and 

 the adequate stimuli, leading to receptors after ages of impact and 

 consequent hammering out pathways through certain reflex-arcs 

 until the required weapons of offence or effectors were organised 

 into a defensive-offensive system — were there in profusion. But a 

 great and fundamental principle of the evolutionary process such 

 as Selection is not honoured by being dragged in, even for forensic 

 purposes, to account for results which owe to the search for 

 comfort their perfection of organisation. I have personally seen 

 in some professional invalids of the softer sex nearly as perfect 

 adaptations to their comfort which in no way contributed to 

 their length of life. This may be put aside as irrevelant but it 

 is at least suggestive. 



I su bmit the statement as to the scratch -reflex in the dog that 

 from beginning to end it is an indifferent mechanism and the prob- 

 ability is immense that its initial stages were governed alone by 

 repeated stimuli from parasites which produced receptors, con- 

 ducting fibres afferent neurones and efferent neurones, leading 

 into the Final Common Path controlling the flexors of the hind 

 limb. It would then come under the Law of Subjective or Hedonic 

 Selection formulated by Professor Stout in the words : " Lines of 

 action, if and so far as they are unsuccessful, tend to be discontinued 

 or varied ; and those which prove successful to be maintained. 

 There is a constant tending to persist in those movements and motor 

 attitudes which yield satisfactory experiences, and to renew them 

 when similar conditions recur ; on the other hand those movements 

 and attitudes which yield unsatisfactory experiences tend to be 



