On diseases of the skin : a system of cutaneous medicine / by Erasmus Wilson, F.R.S.

  • Wilson, Erasmus, Sir, 1809-1884.
Date:
1867
Catalogue details

Licence: Public Domain Mark

Credit: On diseases of the skin : a system of cutaneous medicine / by Erasmus Wilson, F.R.S. Source: Wellcome Collection.

    957/1058 (page 875)
    body, with a whip-like appendage in front, and along one of its sides several fine fibres. Again, as the animalcule of the hair-follicles has not yet, as we conjecture, been seen in its ^perfect shape, it is possible, although little probable, that this last stage of development may correspond with some already known mite. In no case, however, could the animalcule, for the before-mentioned reasons, become one of the ordinary parasites of the human skin; but this creature must present the remarkable peculiarity of living within the human body in its young state, and in its perfect state of living externally to it. Further researches may serve to establish this question; in the meantime, however, I will designate this animal, from its habitat in the hair-follicles, acarus folliculorum. About six times have I seen, both in the comedones of living persons, and in the hair-follicles of the dead, a heart-shaped body, having a small process projecting from its broader end. This body was somewhat longer than the breadth of the animal, of a brownish colour, and appeared to be filled with a granular sub- stance. In the hair-follicles it was always close to the animalcule, but not connected with it. This observation, with the fact of the non-resemblance of the heart-shaped body to any known human structure, gives force to the conjecture that it must bear some relation to the acarus. It might, for example, be an egg-shell, out of which an embryo has escaped. In reference to the movements of the creature I have been able to make the following observations :—The palpi are capable of being moved in different directions, of being drawn in and stretched out. The latter movements are remarked also in the proboscis, which is sometimes thrust beyond the palpi, and some- times drawn back. The legs can also be moved in various direc- tions, and the creature is often seen to move them backwards and forwards, like a pendulum; they can also be retracted or stretched forth. The thorax and body admit of being curved. Although the creature makes all these movements, it does not walk, but merely changes its position from side to side; once, indeed, I saw an acarus walk a distance equal to his own length, but then it was along a hair, which he closely grasped. Simon remarks, that he saw the first and second described forms most frequently, and the third and fourth forms, namely, that with the short and pointed abdomen, and the slender animal with three pairs of legs, only rarely; the former in the proportion * The trichomonas vaginalis, with which we are well acquainted, bears no resemblance whatever to the steatozoon folliculorum. The trichomonas is a globular sac, slightly drawn out to a point, and having connected with this point a flexible and mobile pedicle, which acts the part of a sucker. The sac measures about j^^j of an inch in diameter. We have not seen Donne's figure.