THE EEGULATION OF NUMBEES 297 



previously maintained cannot be supported. To this we may- 

 agree ; the attribution of the catastrophe is not directly to changes 

 in numbers. In the second passage it is suggested that national 

 fertility may be so much in excess of requirements as to disrupt 

 social organization. To this we cannot agree. In general increase 

 is in response to economic requirements and, when it is in excess 

 and is not within a reasonable time curbed, the conditions which 

 result are not those which, though they may have important 

 consequences, produce the kind of result here attributed to them. 



19. Both war and migration are frequently said to be the 

 consequences of over-population. We may take migration first. 



It may be as well to give some typical expressions of this 

 point of view. Mr. Haddon says, ' when reduced to its simplest 

 terms a migration is caused by an expulsion and an attraction, 

 the former nearly always resulting from a dearth of food or 

 from over-population, which practically comes to the same thing. 

 Sooner or later a time comes when the increase of the population 

 of a country exceeds its normal food supply.' ^ In the Keport of 

 the National Birth-Kate Commission we read that ' a pressure 

 of population in any country brings as a chief historic consequence 

 overflows and migrations into neighbouring and other accessible 

 countries '.^ Professor Myres, speaking of the Greek migrations 

 of the eighth to the sixth centuries b. c, attributes them to the 

 fact that ' population had overtaken the means of subsistence '.^ 



It is not altogether clear what is meant by such statements. 

 Very frequently it seems to be implied that there commonly 

 exists a condition in which there is more than enough food in an 

 area occupied by an existing population, that sooner or later 

 population catches up, so to speak, the food-supply and that 

 migration afterwards follows any further increase of population. 

 We may first look at this point of view. All that has so far been 

 said goes to show that only for very short periods and under very 

 unusual circumstances can there be under any conditions of 

 social organization a state of under-population. Even if we put 



* Haddon, Wanderings of Peoples, p. 1. " The Declining Birth-rate, p. 43. 



* MjTes, Eugenics Review, vol. vii, p. 31. These authors are only repeating what 

 has often been said in former times, as, for instance, by Bacon in the following 

 passage : ' Look when the world has fewest barbarous people but such as commonly 

 will not marry, or generate, except they know means to live (as is almost everywhere 

 at this day except Tartary) there is no danger of inimdations of people. But when 

 there be great shoals of people which go on to populate, without foreseeing means 

 of life and sustentation, it is of necessity that once in an age or two they discharge 

 a portion of their people upon other nations ' {Essay on the Vicissitude of Things). 



