Researches into the structure and development of a newly discovered parasitic animalcule of the human skin, the entozoon folliculorum / by Erasmus Wilson.

  • Wilson, Erasmus, Sir, 1809-1884.
Date:
1844
Catalogue details

Licence: Public Domain Mark

Credit: Researches into the structure and development of a newly discovered parasitic animalcule of the human skin, the entozoon folliculorum / by Erasmus Wilson. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    longest specimen I have seen. The body of this animal, from the snout to the base of its posterior legs, measured 2-5-0, and the greatest breadth of the thorax -5^ of an inch. Of the smallest there were two specimens, of which the same measure- ments were— Entire length. 100 1 100 Length of hody. 1 2 8 0 1 312 Greatest breadth. 1 48 0 1 5 5 5 1 6 0 Of fifty specimens, the largest number measured in extreme length from ^ to of an inch. In length of body the greatest number measured (in round numbers) in length of head greatest breadth 5^ of an inch. 2T^, X0005 5iv.c*iv>o», Uiwu-uiii 5 00 The short form varies in extreme length from xio to of an inch. The shortest specimen that I have met with measured in length, namely, from the snout to the base of the posterior legs, 3^? and in greatest breadth, xio- The longest, namely, that which measured in extreme length xw? measured in length of body 3^5 and in greatest breadth -5^ of an inch. Turning my attention to the development and mode of growth of the Entozoon, I met with some curious results,—results that led me to the conclusion that the two varieties are developed in a manner peculiar to each ; that both proceed from ova, but that the larger kind pass through an intermediate developmental form in which the shorter do not participate. Probably this peculiarity may depend on some un^ known modification of the elements of nutrition, and, very possibly, on the same cause with that which determines the greater length of the animalcule. In reflecting on this peculiarity I was reminded of the modification which the young of the com- mon earth-worm presents in a soil of variable tenacity, in the one case being extruded from the oviduct of the parent surrounded by a nidarnental covering, and in the other in its perfect state. Here is an important modification having reference to the security of the young; the peculiarities in development of this Entozoon may have an analogous purpose. The oya of the Entozoon folliculorum are bodies of considerable size, and, as I failed in discovering any body of similar proportions within the abdomina of the many hundred animals which I have examined, I came to the conclusion that in their earlier state they were the nucleated cells which so commonly formed a cluster within the caudal extremity of the abdomen, and that these cells underwent development out of the body of the animal. I was strengthened in this view by occasionally finding small masses of these cells in the neighbourhood of the Entozoon. These masses were of an amber colour, and composed of nucleated cells, each of which measured about xtW of inch in the long and about one-fourth less in the short diameter. In the vicinity of the masses of small cells I frequently saw cells of somewhat larger size (Plate XVI. fig. 12.) composed of secondary cells, and others, of a more or less oval shape, containing within their investing membrane secondary nucleated cells of various size and in considerable number (Plate XVII. fig. 13.). The measurement of 2 s 2