When last we left Dr. Cartwright, the Louisiana physician insisted that black people constitute a separate species from white people, possessing various peculiarities that distinguished them in anatomy and physiology. Those peculiarities in turn made them subject to mental illnesses which caused them to run away (Drapetomania) and to lack work ethic (Dysaethesia Aethiopica). I should say that in the nineteenth century, the word “peculiar” and its derivatives did not have quite the pejorative tinge that they have in our day and with which I employ it in my title. Southerners referred to slavery, among other things, as their peculiar institution but meant it not as we might to call it unpleasantly or suspiciously strange. Instead the word connoted a more value-neutral distinctiveness. To capture the same sense, we might say particular or different.
Cartwright believed black people a separate species but, like a good man of science, he did not simply assume it. Nor did he insist that color alone made the races into two species.
It is commonly taken for granted, that the color of the skin constitutes the main and essential difference between the black and the white race; but there are other differences more deep, durable, and indelible, in their anatomy and physiology, than that of mere color.
Modern biology tries to delineate species on firmer grounds than their appearance or simple gross anatomy, taking as its gold standard evolutionary lineages. But Cartwright lived and wrote before DNA, genetics, and Origin of Species. Insofar as he proceeds from morphological distinctiveness, the Louisiana doctor stands on firm nineteenth century scientific grounds.
Cartwright did not originate the idea that separate races of people constituted separate species. That honor goes to the Father of Taxonomy, Linnaeus himself. He classed humanity into four races based on skin color and continent: white Europeans, red Americans, brown (later yellow) Asians, and black Africans. He later described each as exemplifying one of the four temperaments of Antiquity, respectively sanguine, melancholic, choleric, and phlegmatic.
However, nineteenth century authorities did not all follow Linnaeus. Polygenists, who did follow the Father of Taxonomy, like Cartwright and such Enlightenment luminaries as David Hume and Voltaire, insisted that the various races had different lineages and origins. Polygenists differed on how many races existed and how to divide one from another. Opposing them, monogenists insisted that the various races shared a common lineage. While challenged by monogenists, at the time Cartwright set pen to paper polygenism commanded a healthy share of the academy both in America and France. In the latter no less a figure than pioneering comparative anatomist and paleontologist Georges Cuvier affirmed the separate lineages of human races. In the United States, polygenists included both politically-informed Southerners like Cartwright and Massachusetts-based, apolitical Swiss immigrant Louis Agassiz.
Though I don’t know that he would go so far as Cartwright and the polygenists, I must add another authority’s words on the subject:
I am not, nor ever have been, in favor of bringing about in any way the social and political equality of the white and black races, that I am not nor ever have been in favor of making voters or jurors of negroes, nor of qualifying them to hold office, nor to intermarry with white people; and I will say in addition to this that there is a physical difference between the white and black races which I believe will forever forbid the two races living together on terms of social and political equality.
I came on the passage, to which I added the italics, by serendipity in my reading today. Lincoln spoke those words at Charleston, Illinois on September 18, 1858, while debating Stephen Douglas.