THE EEGULATION OF NUMBERS 241 



species, as such an increase would intensify the struggle between 

 the members of the species — this intensification of the struggle 

 not bringing any corresponding advantages. 



We are ignorant with regard not only to the form of the pre- 

 human ancestor, but also with regard to the conditions under 

 which he lived. We must suppose, however, that his fecundity, 

 like that of any other species in a state of nature, was of a strength 

 that enabled a sufficient proportion of his offspring to survive 

 the unavoidable dangers. As we have seen, that which marks 

 the setting out of man on the path which led to the dominion 

 over all other species was the growth of his intellect. The most 

 obvious consequence of this increase in intellectual power must 

 have been to enable man to protect himself against many of these 

 dangers. We do not know to what dangers he was subject, but 

 they must in all probabiHty have been many and serious in view 

 of his relatively poor equipment with means of defence. Yet 

 we have only to look at the Tasmanians to find that, when a 

 degree of skill had been reached not far superior to that of Lower 

 Palaeohthic man, he had freed himself from most of these dangers. 

 Parasites were not then, so far as we can tell, a serious menace, 

 and against the attacks of other species he could defend himself 

 with almost complete success. Whether his fecundity had come 

 to differ from that of the pre-human ancestor by that time we 

 cannot tell ; in any case the fecundity of prehistoric man was 

 evidently in the main a legacy of the pre-human ancestor — a 

 degree of fecundity that had been evolved in the face of quite 

 other conditions. Since the time of prehistoric man fecundity 

 has increased — this increase being apparently in the main in 

 the nature of a modification due to changed conditions of life. 



It appears that we must regard the growth of intellect as 

 having enabled man to avoid the serious consequences which 

 a fecundity in excess of that necessary to ensure survival would 

 otherwise have brought about. Excessive fecundity, not there- 

 fore being a disadvantage, was not reduced by selection. It 

 must be remembered that human fecundity is only relatively 

 excessive ; actually man is a slow- breeding animal, and when we 

 speak of this relatively excessive fecundity, we are not to think 

 of such a degree of fecundity as would occupy so prominent 

 a place among the bodily functions as to render man less adaptive 

 than he would have been had it been less. Fecundity, in other 



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