Parasites: A Treatise on the Entozoa of Man and Animals / Including Some Account of the Ectozoa

by T. Spencer Cobbold

The museum of the Royal College of Surgeons of England contains some of the finest specimens of hydatids from the lower animals that are to be seen anywhere, the very choicest of them having been selected by Hunter himself. That distinguished man sought information from every available source, and hydatids were for him of almost equal interest, whether found in the body of a human being or in the carcase of an ox or an ass. Now, at all events, neither pathologists nor sanitarians can well afford to neglect comparative pathology; and, for myself, I am free to say that the yearly exposition to the students of the Royal Veterinary College of the phenomena of parasitic life amongst animals has brought with it an ever-increasing knowledge of the most curious and often unlooked-for information. Some of the data thus supplied are quite remarkable. Let me also add that my studies of the entozoa of wild animals have put me in possession of particulars of high value in regard to the larger question of the origin of epidemics. Beasts, birds, reptiles and fishes, of every description, are liable to succumb to internal parasites, and there is practically no end to the variety of useful information to be obtained from this source. I have collected materials almost sufficient for a separate treatise on this department of the subject, but I fear I shall never have either the time or opportunity to give the facts due publicity. Here, for obvious reasons, I must for the most part restrict myself to the hydatids properly so called.

Referring, in the first instance, to the hydatids of animals that have the same mode of origin and exhibit the same general characteristics as those found in man, I notice that four of the metropolitan museums exhibit nine examples of liver Echinococci. The Hunterian Collection shows specimens of this kind from the pig, monkey, zebra, and lion. The museum at St Bartholomew’s Hospital contains two examples from the pig and one from a cow; whilst the animal liver-hydatids preserved in the King’s College and Guy’s Museums, respectively, are from the pig and sheep. That from the latter is partly calcified. Respecting animal hydatids affecting the lungs, the Cambridge Museum exhibits a simple acephalocyst from a monkey, and the Guy’s Hospital Museum shows a pulmonary hydatid from the kangaroo. In the museum at Oxford, Dr Acland’s (pathological) department shows a preparation of “one large echinococcus cyst from the abdomen of a baboon,” whilst Dr Rolleston’s department (anatomical) displays the echinococcus itself from the “cavity of the abdomen of the same animal.” The collection also contains a variety of other bladder worms from different animals. The Hunterian Museum, Lincoln’s Inn, exhibits four or five alleged examples of hydatids from the kidney of the sheep, besides another from the spleen. Some of these are of very doubtful character. A cystic kidney from the sheep, preserved in the London Hospital Museum, and originally supposed to have been due to hydatids, is (as hinted in the MS. catalogue) certainly not of parasitic origin. In regard to the occurrence of hydatids in the heart of animals the Hunterian series shows two good examples from cattle, whilst the collection at University College exhibits one taken from the wall of the left ventricle of a sow. This was presented by Dr Elliotson.

In the museum of the Royal Veterinary College there are a number of excellent preparations of true hydatids taken from various animals, especially from cattle, swine, and sheep; and there are also many kinds of bladder worms which, though often called “hydatid” by veterinarians, have a totally different origin from that of the true Echinococci. The so-called gid-hydatids (Cœnuri) and slender-necked hydatids (Cysticercus tenuicollis) are of this description. Specimens of the polycephalous brain hydatid, or Cœnurus, also exist in the museums connected with St Bartholomew’s, Guy’s, and St Thomas’s Hospital Medical Colleges, as well as in both the anatomical and pathological departments of the Oxford Museum. Specimens of large Cœnuri occurring in the soft parts of rabbits may be seen in the Guy’s Museum (presented by Mr Carpenter). Similar characteristic specimens exist in the Oxford Collection, labelled C. cuniculi, obtained from the “masseter and infraspinatus” muscles of a rabbit. My private collection also contains a recent addition of this remarkable hydatid, sent to me by Mr Alston from Ayrshire. It is the only one I have seen from Scotland. In the second half of this work these Cœnuri will again come under notice. Three examples of the slender-necked hydatid (from a monkey and two sheep respectively) may be seen in the Guy’s and University College Collections, and there are several in the museum of the Royal Veterinary College.

I cannot go out of my way to speak of other bladder worms, except so far as to call attention to the heart of a bear preserved in the museum at Guy’s, the walls of which are crowded with Cysticerci. That unique preparation ought to be carefully examined and described. The Hunterian Museum contains two magnificent specimens of hydatids affecting the bones of cattle. In the one case a solitary vesicle occupies the shaft of the humerus; whilst in the other several “acephalocysts” have taken up their residence within the cancellous structure of the ilium.

In the matter of human mortality from hydatids I have already supplied statistical evidence of the unenviable distinction which our Australian colonies exhibit, and in addition to the facts brought forward I may add that Dr Lewellin has mentioned to me a fatal case in which an hydatid occupied the whole length of the vertebral canal. The patient was under Dr Annand’s care. There could be no doubt as to the genuineness of the case, as the spinal cyst was tapped during life, when echinococcus hooklets were found.

Through Dr Lewellin I am also indebted to Dr H. B. Allen, pathologist at the Melbourne Hospital, for the particulars of a case of hydatids of the cerebrum, which are given as follows:

“J. Q—, aged 15, was admitted into the Melbourne Hospital on the 13th November, 1877, suffering from partial left hemiplegia. He rapidly became insensible and died next day. His mother furnished the following history.

“He had been woodcarting in the bush for a considerable time, and while thus engaged eight weeks before admission began to lose power in his left arm and leg; gradually the paralysis increased, and he was taken home, where he remained for six weeks. During this time he had every week an attack of severe headache, and once he lost all sight for over half an hour. Gradually the symptoms increased, and he was taken to the hospital, but even then was able to walk with assistance part of the way.

“At the autopsy, when the calvarium was removed, a large cyst about four inches in diameter was found on the mid-convexity of the right hemisphere of the cerebrum, slightly towards its anterior part. It formed a marked prominence on the anterior surface of the brain, and was bounded superficially by the pia mater and arachnoid, which were neither noticeably thickened nor adherent to the dura mater. On opening the cyst it was seen to extend inwards and abut on the wall of the lateral ventricle, and consisted of the ordinary gelatinous membrane, studded internally with little granular eminences, some pellucid, some opaque white. The contents were thin limpid fluid. The brain tissues around presented scarcely any induration. All other organs structurally healthy, congestion being the only morbid condition present.