15 Loc. cit., p. 128.
16 Ziemssen, loc. cit., p. 443.
17 American Journ. Med. Sciences, July, 1876.
18 Loc. cit., p. 715.
Mitchell has written upon the relation between race and chorea. He states that in answer to a circular bearing on this question, sent out by the Smithsonian Institution, he has received a large number of letters from physicians in our Southern States and the West Indies. The general testimony was that chorea is rare among negroes.
Among the exciting causes of chorea are fright or mental apprehension of some kind. Of my 279 cases, 44 were ascribed to fright.
Malaria has been pointed out as influencing the production and course of chorea. Kinnecut has reported some cases in which the movements were aggravated with a certain periodicity.
Chorea may also be brought on by reflex irritation from nerve-injury. In a case which I saw in the practice of John H. Packard several years ago there was an injury to one of the digital nerves of the thumb from a splinter, which was the apparent cause of an attack of chorea; a portion of the nerve was excised, and the chorea ceased in a short time.
I have lately seen a case in which an attack of chorea came on apparently in consequence of a severe mash of the finger. The finger had been crushed by the runner of a sled, and the choreic movements began before the wound was healed.
Hamilton19 has found chorea associated with eczema. He saw a case in which eczema of the calves of the legs and of the scalp developed at the same time with an attack of chorea. Both got well about the same time.