THE NUMBERS OF MEN 87 



accurately the general situation than the apparent rates derived 

 from the figures of estimated total world population. 



In the light of the data presented it may be tentatively sug- 

 gested that the population of the world as a whole has been 

 growing in the recent past at a rate of something of the order 

 of one per cent per annum — perhaps a little more, perhaps a 

 little less, but at about that figure. This would mean, if con- 

 tinued without change, a doubling of the present world popula- 

 tion in about seventy years. There is, however, no reason to 

 suppose that the total population of the world will ever, in its 

 present cycle of growth, at least, be double what it is at the 

 present time. 



It seems reasonable to conclude from a great body of avail- 

 able data that the mean annual growth rate per cent for the 

 world population is steadily decreasing at the present time, and 

 has been during the recent past. In other words there is a general 

 decline of fertility that appears not to be exclusively confined to 

 highly "civilized" countries, where the populations are most 

 sophisticated and eager and adept at birth-controlling. It seems 

 rather to be a world embracing phenomenon — something affect- 

 ing man as a species. But, as will appear clearly in a moment, 

 it is a phenomenon of historically very recent appearance, in 

 comparison with man's total span of existence on the earth as a 

 distinct species. The world-wide decline in fertility is certainly 

 a much more recent thing than the making of efforts at contra- 

 ception. On the evidence it appears likely that the marked slow- 

 ing up of the growth rate of world population per unit of time 

 did not begin until about the beginning of the present century, 

 or in the preceding decade. But nearly two centuries ago Short, 

 in his entertaining treatise on the population of England — per- 

 haps history's most venomous diatribe against the establishment 

 of hospitals and homes for foundlings, usually considered an 

 innocent form of altruistic behavior — has repeated references to 

 the prevalence of contraceptive practices. As an example he 

 deplores the fact that in "Cities and great Towns . . . the 

 wicked Arts of preventing Conception are more generally known 



