184 THE LAW OF BIRTHS AND DEATHS 



of our own population, and also yield a suitable margin 

 for emigration to the colonies which are in need of popula- 

 tion. But at present our birthrate is utterly unregulated. 

 We are obtaining the largest proportion of children from 

 the least fit, and the smallest proportion from the ablest 

 sections of the population. And all through human 

 history the spectacle has been one of periods of gross 

 over-reproduction, with disastrous economic consequences, 

 alternating with periods of under-reproduction and de- 

 population. 



To obtain an intelligently regulated birthrate, we must 

 first acquire a clear insight into the laws which govern 

 fertility, and devise some means of overcoming at will 

 the rapidly increasing sterility now making itself manifest 

 through all classes. Seeing that such vast increases in 

 the fertilising power of the sperm cells and in the fertilisa- 

 bility of the egg cells can be obtained by such slight and 

 simple means as shown in the experiments of Loeb and 

 others, the possibility that we may find some simple 

 means of ensuring fertilisation in the case of human 

 beings is by no means a forlorn hope. The task may 

 prove unexpectedly easy. It seems to be merely a matter 

 of bringing these influences temporarily to bear on the 

 germ cells. 



Probably the most hopeful way of influencing the gernl 

 cells is through the medium of the blood. As their nutritive 

 condition will no doubt be determined by the quantity 

 and quality of the blood supply, it is desirable that we 

 should know the effect on fertility of an increase of the 

 alkalinity, acidity, and salinity of the blood. This should 

 be readily ascertainable by means of simple and harm- 

 less experiments on unicellular organisms and the lower 

 animals. 



There are in the body certain glands which secrete 



