HUMAN POPULATION IN THE FTJTUBE. 531 



an intenser strain a mentally-laborious life. The greater 

 emotional and intellectual power and activity above con- 

 templated, must be understood as becoming, by small incre- 

 ments, organic, spontaneous, and pleasurable. As, even when 

 relieved from the pressure of necessity, large-brained Euro- 

 peans voluntarily enter on enterprises and activities which 

 the savage could not keep up even to satisfy urgent wants ; 

 so, their still larger-brained descendants will, in a still higher 

 degree, find their gratifications in careers entailing still 

 greater mental expenditures. This enhanced demand for 

 materials to establish and carry on the psychical functions, 

 will be a constitutional demand. We must conceive the 

 type gradually so modified, that the more-developed nervous 

 system irresistibly draws off, for its normal and unforced 

 activities, a larger proportion of the common stock of nutri- 

 ment; and while so increasing the intensity, completeness, 

 and length of the individual life, necessarily diminishing the 

 reserve applicable to the setting up of new lives no longer 

 required to be so numerous. 



Though the working of this process will doubtless be 

 interfered with and modified in the future, as it has been 

 in the past, by the facilitations of living which civilization 

 brings; yet nothing beyond temporary interruptions can so 

 be caused. However much the industrial arts may be im- 

 proved, there must be a limit to the improvement; while, 

 with a rate of multiplication in excess of the rate of mor- 

 tality, population must continually tread on the heels of 

 production. So that though, during the earlier stages of 

 civilization, an increased amount of food may accrue from a 

 given amount of labour, there must come a time when this 

 relation will be reversed, and when every additional incre- 

 ment of food will be obtained by a more than proportionate 

 labour : the disproportion growing ever higher, and the dimi- 

 nution of the reproductive power becoming greater. 



375. There now remains but to inquire towards what 



