136 THE LAW OF BIRTHS AND DEATHS 



the black man riots in comparative abundance, but during 

 the rest of the year . . . the struggle for existence becomes 

 very severe.' " x But as Dr. Westermarck quotes Mr. 

 Oldfield as declaring that the annual pairing season in 

 Western Australia takes place about the middle of spring, 

 this would result in all the births occurring about the 

 middle of winter, the season when the children would 

 have least chance to survive. Therefore any attempt 

 to account for the seasonal fluctuations of the birthrate 

 as the result of pairing seasons and natural selection is 

 hopeless. 



To trace in the seasonal fluctuations of the birthrate 

 the action of the principle advocated here is rendered 

 exceptionally difficult by the complexity of the factors. 

 Thus during the harvest season food is very abundant. 

 It is a season of high feeding. But it is also a season 

 of strenuous work, and it would be difficult to decide 

 whether the high feeding or the hard work would be the 

 most potent factor in affecting the birthrate. Still, as 

 the winter season is undoubtedly the hardest period in 

 most countries, it is during that season that we should 

 expect, on this theory, the maximum number of concep- 

 tions to occur. 



The amount of evidence available is limited, but such 

 as there is tells distinctly in favour of the theory. Wester- 

 marck provides a quantity of evidence bearing on the 

 point, the most important of which is contained in the 

 following passage : "In the northern parts of Europe 

 many more conceptions take place in the months of May 

 and June, when the conditions of life are often rather 

 hard, than in September, October, and November, when 

 the supplies of food are comparatively plentiful. In the 

 north-western province of Germany, as well as in Sweden, 

 1 The History of Human Marriage^ Westermarck. 



