By a series of measurements based, confessedly, upon insufficient data, it is concluded that the Negro has a smaller lung capacity, smaller chest expansion, and a higher rate of respiration than the white man, and that the Mulatto is inferior to both the parent races in these vital functions. These differences are considered a powerful factor in lung degeneration, and proof positive of physical inferiority. In these respects he tacitly repudiates his erstwhile principle that "a physiological law may hold good for one race and not for another," and assumes that the two races are subject to like conditions of disease and death. On the whole it may be said that this is the least interesting chapter in the whole book. The data are so slender and the arguments are so evidently shaped to a theory, that we are neither enlightened by the one nor convinced by the other. But the author's judgment must be justified. The gloomy warning comes with Catonian regularity at the end of each chapter. Listen to his last words: "A combination of these traits and tendencies must in the end cause the extinction of the race."[39] If the Negro is inferior in vital function and power to the Caucasian, he will be a public benefactor who scientifically demonstrates the fact. But the colored race most stubbornly refuses to be argued out of existence on an insufficient induction of data and unwarranted conclusions deduced therefrom. CHAPTER IV. _Subject._ Amalgamation. _Gist._ "The crossing of the Negro race with the white has been detrimental to its true progress and has contributed more than anything else to the excessive and increasing rate of mortality from the most fatal disease, as well as to its consequent inferior social efficiency and diminishing power as a force in American national life."[40] The importance of this proposition is apparent when we consider that the Negroes in this country are a thoroughly mixed people. The pure African type has been well nigh obliterated. It is pointed out also that the mongrel progeny has been produced by illicit intercourse between the white male and the black female. The moral and conservative qualities of a race reside in its womanhood. The Negro people, then, have missed these transmitted qualities. The author is either ignorant of or ignores the large class of mixed Negroes who are the legitimate offspring of colored parents, but would place the whole class under the ban of bastardy. After judicially balancing the testimony furnished by world-renowned authorities upon the effect of race crossing, the author espouses one side of the contention with all the ardor of a retained advocate. Three points are sought to be established. I. THE MULATTO IS PHYSICALLY INFERIOR TO BOTH PARENT RACES. The opinions of examining surgeons during the civil war are quoted which quite unanimously show that the Mulatto is strongly inclined to consumption, scrofula, and vicious taints of blood.