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‘XXXV. Description of a Microscopic Entozoon infesting the Muscles of the Human Body. 
By Ricnarp Owen, Esq., F.R.S. & Z.S., Assistant Conservator of the Museum of the 
Royal College of Surgeons in London. 
Communicated February 24, 1835. 
Upwarbs of fifteen distinct kinds of Entozoa, or internal parasites, are already 
known to infest the human body ; but none have been found of so minute a size, or 
existing in such astonishing numbers, as the species about to be described. 
The body of an Italian, zt. 50, who had died in St. Bartholomew’s Hospital, was 
brought into the dissecting-room, and it was observed by Mr. Paget, an intelligent stu- 
dent, that the muscles presented an uncommon appearance, being beset with minute 
whitish specks. This condition of the muscles had been more than once noticed by 
my friend Mr. Wormald, the Demonstrator of Anatomy, in subjects dissected at St. Bar- 
tholomew’s during previous anatomical seasons. His attention had been especially 
called to it on account of a gritty sensation sometimes perceived in dissection, from 
which circumstance, and the rapid blunting of the scalpels employed, he was induced 
to consider the appearance as being caused by a deposition of specks of earthy matter. 
Mr. Wormald having.acquainted me with this fact, I expressed a desire to be furnished 
with portions of muscle so affected, and through my friend’s prompt attention, I soon 
received ample materials for microscopical examination from the subject above men- 
tioned}, 
With a magnifying power of an inch focus the white specks in the muscle are 
seen to be cysts of an elliptical figure, with the extremities in general attenuated, 
elongated, and more opake than the body (or intermediate part) of the cyst, which 
is, in general, sufficiently transparent to show that it contains a minute coiled-up worm. 
On separating the muscular fasciculi the cysts are found to adhere to the surrounding 
cellular substance by the whole of their external surface, somewhat laxly at the middle 
dilated part, but more strongly by means of their elongated extremities, so as to ren- 
der it generally a matter of some difficulty to detach them: When placed upon the mi- 
crometer they measure ;,th of an inch in their longitudinal, and -+,th of an inch in their 
transverse diameter ; a few being somewhat larger, and others diminishing in size to 
about one half of the above dimensions. They are generally placed in single rows, 
parallel to the muscular fibres, at distances varying from half a line to a line apart 
' The existence of the Entozoon was at the same time satisfactorily determined by Mr. Paget, with the 
assistance of Mr. Brown and Mr. John Bennett, at the British Museum. 
