THE FALL OF THE BIRTH-RATE 37 



In the case of Belgium there was a sharp rise of 

 10 per cent, from 1846-55 to the following decade, 

 and a steady fall thenceforward. So in this case there 

 are two interesting points. In the first place the fall 

 began before 1875. In the second the fertility of the 

 decade 1846-55 was lower than that of any subse- 

 quent decade before 1886-95. As in the case of Con- 

 naught the question arises as to the cause of this low 

 fertility in the early period: France showed then a 

 fertility higher than that of the following decade. 



No doubt one would like to have much more ex- 

 tensive data reaching much further into the remote 

 past, but so far as they go these figures do confirm 

 our previous conclusion that fertility cannot be re- 

 garded as rigidly fixed would it not be a most 

 amazing thing if it were rigidly fixed ? a phenomenon 

 almost without parallel? but that it may exhibit 

 depression in countries and at times when it is im- 

 probable that artificial methods of contraception can 

 be adduced as an explanation. 



Personally, then, I think we can clearly conclude: 



(i i) The recent fall in fertility has not been effected 

 solely or mainly by the use of artificial methods of 

 contraception. The only definite data we possess are 

 against this view. 



(12) In general, fertility cannot be regarded as a 

 fixed quantity for a given nation, but is subject to 

 natural fluctuations. 



As regards the nature of such fluctuations two 

 views have been advanced. Dr Brownlee (ref. 9) has 

 advanced the view that the fluctuations are physio- 

 logical in character, rhythmic variations (not of any 

 i period) in " germinal vitality," analogous to 

 e outbursts of vital energy which lead in the case 

 of an infective organism to epidemics, in the case of 

 higher forms of life to such phenomena as plagues 



