John Langdon Down is a 19th century physician best known for his description of what is known today as Down's syndrome.
I know that Down attempted to classify various types of mental disorders by ethnic characteristics. However, I came across the claim that he believed that evolution was reversed in those with Down's syndrome.
Langdon Down attributed the condition to a "reversion" to the "mongoloid race." He held that evolution had been reversed and there had been a sort of backslide from the superior Caucasian to the inferior Oriental race.
In the paper, however, I cannot find the words reversion or mongoloid, though he does say "mongoloid type."
His original paper reads in conclusion:
The tendency in the present day is to reject the opinion that the various races are merely varieties of the human family having a common origin, and to insist that climatic, or other influences, are insufficient to account for the different types of man. Here, however, we have examples of retrogression, or at all events, of departure from one type and the assumption of the characteristics of another. If these great racial divisions are fixed and definite, how comes it that disease is able to break down the barrier, and to simulate so closely the features of the members of another division. I cannot but think that the observations which I have recorded, are indications that the differences in the races are not specific but variable.
These examples of the result of degeneracy among mankind, appear to me to furnish some arguments in favour of the unity of the human species.
His use of the word "retrogression" might be what this claim is referring to, however, when I read it, it seems that he is not advocating racial superiority, but challenging it.
Did John Langdon Down expand on this paper? Can this claim be confirmed, that he believed in a "reversing evolution" cause for some or all such syndromes?