72 THE WANDERINGS OF ANIMALS [OH. 



by them and dies. The plague has wrought its own 

 remedy. 



Now let us consider man. With the present rate 

 of British increase (an annual gain of 14 per 1000) 

 the population doubles itself in about 50 years. If 

 we apply this rate, which is not at all excessive, to 

 the present 1600 million people of the whole world, 

 there would be, 1000 years hence, a total population 

 of 1660 million millions ; and the whole land surface 

 of the globe would not afford sufficient standing 

 room for this number of people. 



If we apply the same rate backwards, we find that 

 five people, starting 400 Anno Domini, would have 

 been sufficient to produce the present world's popu- 

 lation. So far as actual conditions are concerned 

 this is pure nonsense, but let us consider that : 



1. A population cannot hold its own unless every 

 potential couple is some day supplanted by another. 



2. A population cannot increase, unless, on the 

 average, there are more than two children, not only 

 born, but brought up to propagate the race. 



3. It is absolutely certain that the origin of man, 

 as such, dates back into the Pliocene, a time of which 

 300,000 years would be a conservative estimate, and 

 for argument's sake representing 10,000 generations 

 of mankind. 



p 



4. If we assume that the human race started 

 as the traditional Adam and Eve pair, within the 



