68 The Recapitulation Theory and Human Infancy 



more advantageous plan, incidental with the lower groups but 

 characteristic of the higher, in which parental care in some form 

 is involved. In its early organic and unconscious expressions 

 parental care was manifested in the safeguarding of germ-cells 

 in the coming together of the sexes. Subsequently the hatching 

 eggs were variously and increasingly protected, notably in the 

 brooding of birds and in the placental gestation of mammals. 

 The extension of parental care to the post-natal period opened 

 the way to the evolution of conscious parental solicitude, gradu- 

 ally increasing in duration and intensity. The breeding rate 

 is found to vary with the increasing scope and degree of care 

 from parents. The decrease in the number of eggs and young 

 is associated with a higher nervous organization expressing itself 

 especially in intelligence, and helplessness is made concomitant 

 with intelligence as its necessary condition. 



The peculiar utility of parental care, according to Sutherland, 

 consisted in providing an opportunity for variation in the direction 

 of increasing intelligence. Intelligence in any large amount is nec- 

 essarily associated with delay in the assumption of life-saving abili- 

 ties. Among those animals without parental care variations favoring 

 intelligence, with its coincident delay of maturity, would have been 

 immediately rendered futile by the extinction of the immature 

 animal. There were therefore strict limits to any extension of 

 intelligence among the lower groups. It would increase only to a 

 degree not inconsistent with an independent struggle for existence. 

 With the coming of parental care the way was cleared for an 

 indefinite amount of variation in the direction of intelligence, 

 and thus it is that intelligence is peculiarly the possession of the 

 higher mammals. 



All these contributions to the discussion of infancy and paren- 

 tal care showed clearly that infancy and biological superiority 

 are causally related without indicating just how the associated 

 plasticity of the nervous system was used to bring the improved 

 adaptation about. This last has been done by the psychologists. 

 In connection with his studies upon young animals, reported es- 

 pecially in "Habit and Instinct" (1896), Lloyd Morgan demon- 

 strated with considerable particularity how the imperfect instincts 

 with which the young of learning animals come into the world 

 are adapted to the peculiar circumstances of their existence by the 



