It is not a quote taken out of context.  The entire book talks about which race/nationality is preferable to the other and how certain "lesser" races/nationalities ought to be kept from making a large impact on the collective gene pool.  Why don't you read The Old World in the New?  ( http://books.google.com/books?hl=en&id;=wq0JAAAAIAAJ )  Even a brief skim over the material shows it to be a book dedicated to cataloging the different races and nationalities and their respective detrimental or beneficial impacts .  Here are the section headings of one of the chapters (American Blood and Immigrant Blood) within the book:

"Primitive types among the foreign-born"
"How immigration will affect good looks in this country"
"Effect of crossing on personal beauty"
"Stature and physique of the newer immigrants"
"Do they revitalize the American people?"
"Race morals of the Southern European stocks"
"Are the immigrants good samples of their own people?"
"Appraisal of the different ethnic strains in the American people"
"Rating of the present immigrant streams"
"How immigration has affected the fecundity of Americans"
"Evading a degrading competition by race suicide"
"The triumph of the low-standard elements over the high-standard elements"

This is obviously not a matter of conjecture or personal opinion.  The book might as well be called Eugenics For Dummies.