The significance of such figures in natural selection must be evident. Pittsburgh, like probably all large cities in civilized countries, breeds from the bottom. The lower a class is in the scale of intelligence, the greater is its reproductive contribution. Recalling that intelligence is inherited, that like begets like in this respect, one can hardly feel encouraged over the quality of the population of Pittsburgh, a few generations hence. Of course these illiterate foreign laborers are, from a eugenic point of view, not wholly bad. The picture should not be painted any blacker than the original. Some of these ignorant stocks, in another generation and with decent surroundings, will furnish excellent citizens. But taken as a whole, it can hardly be supposed that the fecund stocks of Pittsburgh, with their illiteracy, squalor and tuberculosis, their high death-rates, their economic straits, are as good eugenic material as the families that are dying out in the more substantial residence section which their fathers created in the eastern part of the city. And it can hardly be supposed that the city, and the nation, of the future, would not benefit by a change in the distribution of births, whereby more would come from the seventh ward and its like, and fewer from the sixth and its like. Evidently, there is no difficulty about seeing this form of natural selection at work, and at work in such a way as greatly to change the character of one section of the species. For comparison, some figures are presented from European sources. In the French war budget of 1911 it appears that from 1,000 women between the ages of 15 and 50, in different districts of Paris, the number of yearly births was as follows: Very poor 108 Poor 99 Well-to-do 72 Very prosperous 65 Rich 53 Very rich 35 Disregarding the last class altogether, it is yet evident that while the mother in a wealthy home bears two children, the mother in the slums bears four. It is evident then that in Paris at the present time reproductive selection is changing the mental and moral composition of the population at a rapid rate, which can not be very materially reduced even if it is found that the death-rate in the poorer districts is considerably greater than it is on the more fashionable boulevards. J. Bertillon has brought together[67] in a similar way data from a number of cities, showing the following birth-rates: