ON THE ANATOMY AND PHYSIOLOGY OF THE CYSTICERCUS TENUICOLLIS. BY C. B. ROSE, F.R.C.S., F.G.S., &c., SwAFFHAM. Received April 11th-Read May 9th, 1848. In the year 1833, I contributed a paper on the Vesicular Entozoa,* to the London Medical Gazette, in which, I fear, I did little more than repeat the errors of my predecessors; still, in that imperfect summary, I did call the attention of zootomists to the existence of an organ, hitherto unobserved, which I had discovered in my examinations of the Cysticercus tenuicollis, and which is readily observed within the caudal vesicle, suspended from that portion where what has been called the body of the entozoon terminates and the vesicle commences. I long hoped that the above notice would have caught the eye of some comparative anatomist possessing more facilities for the investigation than myself, and have incited him to undertake a more elaborate dissection of the entozoon; but my anticipations not having been realized, I again took up the subject, and the result of my researches I have now the honour of laying before the Fellows of this Society. Previously to entering upon the history of my own inquiries and dissections, I will briefly trace chronologically the steps of preceding naturalists in the examination of this genus of the entozoa Cystica. As early as the year 1654, Bartholin cursorily described * London Medical Gazette, 1833, vol. xiii. p. 205. Hydatids (believed by Rudolphi to be Cysticerci), which he considered to be animated, but did not esteem them to be worms.* About the same period, Steno discovered bladders (Cysticercus tenuicollis) in the omentum of a rein-deer, which he described as if pregnant, or containing one within another.† It is most probable that Steno mistook the omental cyst for the parent hydatid, and the true parasite for the offspring; the cyst being commonly so transparent, as to give it very much the appearance of a bladder of water, suspended by a pedicle. Hartmann, in the year 1685, was the first to pronounce this hydatid to possess independent vitality, he having placed one (which he had taken from the omentum of a goat) in warm water, and observed its undulatory movements. also noticed the retracted neck and head. He Our countryman, Tyson, in 1691, made discoveries to the same extent, without being aware of what Hartmann had published. Tyson considered the caudal vesicle to be the stomach of the worm. His paper (published in the Philosophical Transactions) is entitled, "Lumbricus hydropicus; or, an Essay to prove that Hydatides, often met with in morbid animal bodies, are a species of Worms, or Imperfect Animals."S Pallas, who wrote in 1766, was the first to enter elaborately into the natural history of vesicular worms: having minutely examined this hydatid, and imagined that its mouth resembled that of the Taniæ, he named it Tænia hydatigena.|| Gocze, Zeder, Steinbuck, and Rudolphi, did but perpetuate the errors of their predecessors, contributing nothing to the knowledge previously acquired respecting their anatomy and generation. The recent writers on the same subject, of this country, Houston, Knox, Owen, Gulliver, and Goodsir, have * Entozoorum, sive Verm. Intest. Hist. Nat., vol. i. p. 119. + Idem, loc. cit. § Opus cit., vol. i. p. 112. Idem, p. 112. || Elench. Zooph., p. 413; also Spicileg. Zoolog., Fasc. 12, p. 42. made us much better acquainted with the anatomy of this entozoon; to whose contributions I shall have occason to refer, en passant. Till the period of Harry Goodsir's researches, the Cysticercus had been described as made up of a head armed with a double row of hooklets, and furnished with four mouths or suctorial cups, a neck, body, and caudal vesicle; and various had been the offices assigned to these components of the parasite. Of the parts connected with the imaginary head, some authors have considered the hooklets to be for the purpose of attachment to the containing cyst, and the whole body, therefore, an organ of prehension; others have looked upon them as teeth; and a third party thought them subservient to the generative process. With regard to the four oscula, Steinbuck, finding that they were not patent, and consequently could not be mouths, conceived the preposterous notion (as late as 1802), that they performed a respiratory function. Rudolphi and several earlier naturalists described them as true mouths, for the purpose of sucking in nutriment, each mouth opening into a canal, which either passed separately towards the caudal vesicle, or, uniting into one common canal, terminated in the caudal vesicle. Some recent writers have given credence to the above statements of Rudolphi, and also reiterated them; but whoever reads his remarks upon this portion of the subject will be quite satisfied that he had promulgated conjectures rather than observations. The late Dr. Houston, of Dublin, in reference to the so-called mouths, says, "These depressions are called mouths, meaning thereby patulous orifices, but from my own observations I believe them to be covered over by the same kind of transparent membrane as that which completes the anterior planes, for I had abundant opportunities of remarking that the fluid of the caudal vesicle when squeezed along the neck into the head, protruded and rendered them prominent, without making its escape from apertures in their centre." The appearance of their being covered by a An account of Hydatids found in the omentum of an axis-deer. Dublin Journal of Science, &c., vol. viii. p. 271. |