The main focus of the article Applied Eugenics, written by P. Popenoe and R.H. Johnson, is that it would be detrimental to the American gene pool to allow foreigners to immigrate to Unites States soil. This article identifies that, in 1918, there were approximately "14,000,000 foreign-born persons, together with other millions of the sons and daughters of foreigners who although born on American soil have as yet been little assimilated to Americanism" (Popenoe & Johnson, 1918). They argue that foreigners should not be absorbed, as the stock that is incoming is not as hardy as the stock that the original invaders brought with them, as necessitated by the vigorous voyage to, and strenuous establishment on, the shores of the New World. Popenoe et al argued that there was not enough differentiation between the newcomers to support any hybrid vigor.