PROCEEDINGS
OF
THE ROYAL SOCIETY.
March 30, 1843.
GEORGE RENNIE, Esq., V.P., in the Chair.
Joseph Miller, Esq. was balloted for and duly elected a Fellow of the Society.
The following papers were read, viz. —
1. " Researches into the Structure and Developement of a newly discovered parasitic Animalcule of the Human Skin, the Entozoon foUiculoTumr By Erasmus Wilson, Esq., Lecturer on Anatomy and Physiology at the Middlesex Hospital. Communicated by R. B. Todd, M.D., F.R.S.
While engaged in researches on the minute anatomy of the skin and its subsidiary organs, and particularly on the microscopical com- position of the sebaceous substance, the author learned that Dr. Gustow Simon of Berlin had discovered an animalcule which inha- bits the hair follicles of the human integument, and of which a de- scription was published in a memoir contained in the first Number of Miiller's Archiv for 184^2. Of this memoir the author gives a translation at full length. He then states that, after careful search, he at length succeeded in finding the parasitic animals in question, and proceeded to investigate more fully and minutely than Dr. Simon had done the details of their structure, and the circumstances of their origin and developement. They exist in the sebaceous follicles of almost every individual, but are found more especially in those per- sons who possess a torpid skin ; they increase in number during sickness, so as in general to be met with in great abundance after death. In living and healthy persons, from one to three or four of these entozoa are contained in each follicle. They are more nume- rous in the follicles situated in the depression by the side of the nose ; but they are also found in those of the breast and abdomen, and on the back and loins. Their form changes in the progress of their growth. The perfect animal presents an elongated body, di- visible into a head, thorax, and abdomen. From the front of the head proceed two moveable arms, apparently formed for prehension : and to the under side of the thorax are attached four pairs of legs, termi-
