THE INTELLECTUAL OBSERVER.

JANUARY, 1864.

RECENT DISCOVERIES IN ENTOZOOLOGY.

(With a Coloured Plate.)

Ir cannot have escaped the attention of any well-informed reader that the subject of Entozoa, or internal parasites, is daily assuming greater importance; and this, of course, not so much on account of the very curious natural history phenomena which these singular animals exhibit, as on account of the strange part they play in the production of suffering and disease, alike as regards ourselves and the animal creation in general. In the pages of the INTELLECTUAL OBSERVER, one of our contributors (Dr. Cobbold) has supplied us with many interesting facts respecting certain parasitic forms which infest birds, beasts, and fishes; but he has not, at present, said much about the entozoa, whose special prerogative it is to take up their abode in the human body. We have, however, lying before us an important work bearing on this subject, as well as a small brochure, by an author whose name is probably known to some of our readers.* In the larger work, which is as yet incomplete, the author enters very minutely into the structure, mode of reproduction, and general economy of the human parasites, dwelling more particularly on those species which produce fatal results.

Instructive as it might be, it is scarcely necessary to take into consideration the various steps by which the earlier entozoological observers arrived at the conviction that the little watery cysts, or hydatids, found in man were in reality animals; but we cannot allow the present opportunity to pass without rendering a tribute of homage to those recent investigators and discoverers in this department of science, who have, frequently at considerable risk to their own personal comfort, demonstrated the true source and nature of these lowly organized beings. To Dr. Kuchenmeister, above all others, this recognition is due, and it redounds greatly to the credit of Leuckart (who, at the present hour, is legitimately placed at the head of continental helminthologists), that he has, in the writings quoted

"Die menschlichen Parasiten und die von ihnen herrührenden Krankheiten." Von Rudolf Leuckart. Erster Band. Liepsig, 1863.

"Die neuesten Entdeckungen uber menschliche Eingeweidewürmer und deren Bedentung für die Gesundheitspflege." Convers. Jahrb. 1863.

VOL. IV.-NO. VI.

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below, done full justice to the physician (formerly) of Zittau. Thus, in speaking of the small cysticerci, or measles of pigs, whence we obtain one kind of tapeworm, he says:

"Kuchenmeister hit upon the idea of administering the measles as provender to other animals, and of studying the changes which took place in the alimentary canal of the quadrupeds thus fed. Such a trial might very naturally suggest itself to any one, but this does not lessen the merit which belongs to Kuchenmeister, seeing that the result was thoroughly decisive. During the passage of the measles' through the stomach, they lost their caudal vesicle, which part had previously so strikingly distinguished them, the thin walls succumbing to the influence of the digestive fluids; only when the quadrupeds were proper hosts did the cephalic ends of the cysticerci resist the action of digestion. In this case they passed on, together with the contents of the stomach, into the intestines, in order to anchor themselves here by means of their sucking appendages, and also to stretch and grow into the adult tapeworm condition (Jahrb. s. 629)."

Besides these experiments on animals, it is well known that Kuchenmeister was permitted to feed two condemned criminals, to one of whom he administered seventy-five measles of pigs three days before his execution, the other having eaten twenty measles on two separate occasions, at considerable intervals. In the first case ten very young tapeworms, only a few lines in length, were found after death, and in the second experiment nineteen were found, eleven of which had advanced to the condition of maturity. Subsequently, several young men, we are told, voluntarily came forward in the interests of science, and swallowed fresh measles, and three or four months afterwards showed unmistakeable signs of suffering from tapeworm. They were, we presume, deprived of their internal guests by the employment of the ordinary remedies, when, at least, they had satisfied themselves that they had played the part of host long enough.

But it is neither the measles of pork producing the Tania solium of man, nor the measle-like cysticerci of calves and oxen, producing the Tania mediocanellata (equally common amongst our veal and beef-loving community); nor, again, the Oxyuris, vexing children; nor the Trichine of sausages and hams, and the closely allied species of Ascarides (which we probably obtain by drinking unfiltered water); it is not, we say, any of these forms about which we need particularly trouble ourselves just now, but it is in reference to that most fatal of all disease-producing parasites, the so-called Echinococcus, to which we now most especially desire to call attention.

Veterinarians, sheep-breeders, stockmasters, and others

practically acquainted with the diseases of our domesticated animals, are at length exerting themselves to ascertain the best methods by which their flocks and herds may be rendered secure from the invasion of certain of the above-mentioned entozoa; but few, if any, of their number are probably aware how much more disastrous to human life are the larvæ of a small tapeworm which lives in the intestines of the dog. In those countries where this animal is well nigh indispensable to human life, it is at one and the same time both a curse and a blessing. The tapeworm (Tania echinococcus) of the dog produces a larva which annually destroys its hundreds and its thousands of the human race; and sad is it to reflect that the disease thus produced is too often, through sheer ignorance, multiplied and propagated by those who pretend to be able to cure the disease. In happy England fatal cases are of constant occurrence, but it is in Iceland that this disease assumes a formidable endemic character. According to Leuckart and Dr. Krabbe (a pupil of the recently deceased savan, Eschricht, of Copenhagen), who has specially visited the country to investigate the disease, the following facts may be relied on :

"For every 100 inhabitants of Iceland there are 1100 head of horned cattle, and every peasant has on an average six dogs. In Denmark there are 180 cattle to every 100 of the people. There are many of the Iceland doctors who, not unfrequently, have upwards of 100 patients afflicted with the Echinococcus disease under treatment at the same time, the total number of such cases in the island being estimated at 10,000. By far the greater number of these patients, however, are in the hands of quacks, whose influence is the greater, because there are in all Iceland but six legally authorized medical men, each of whom presides over a district of about 1500 square (English) miles, embracing a population of about 10,000 individuals. The treatment of the quacks is exactly suited to keep up the epidemic, for, amongst their remedies, dog's urine and fresh dog-excrement play a conspicuous part. (Jahrb. s. 654.)”

Would

These statistics are truly appalling! We have here a forcible illustration of the falsity of the proverb, which says, "Where ignorance is bliss, it were folly to be wise." it be folly to get up a Social Science Congress at Reikjavik, and, in the name of humanity and intelligence, appeal to the Icelandic parliament to put down these evil practices with the strong arm; at the same time taking every opportunity to enlighten this grossly ignorant population? Superficial, goodnatured unintellectual observers may look on complacently, and even, perhaps, remark that the Echinococcus epidemic is one of those mysterious dispensations of Providence which we ought to accept submissively, without looking too minutely into the

secondary causes concerned in its production. For our part, however, we prefer to read His guidings differently, to sound the aforesaid causes to their lowest depths, to search out the animal parasite which thus afflicts mankind, to subject the little beast to microscopic examination, to watch its growth and development, to work out its anatomy, to study its haunts and habits, to make it the source of a series of experiments; in short, to leave no stone unturned by which we may arrive at a sound conclusion as to the best methods of checking its abundance, and of preventing its destructive assaults upon the welfare of our fellow men. An enlightened public will eventually applaud these efforts; but, as in a crowd, it is only the tallest men who see furthest, so, unfortunately, does it happen that our laborious, self-denying, experimental physiologists gain only the respect of the few; whilst the many, unenlightened, prefer the old paths," not unfrequently, indeed, placing every obstacle they can in the way of those who silently devote their time and talents to studies which are calculated to benefit us all. If it were necessary to exemplify the truth of these remarks, we should refer to the recent attacks made upon experimental physiologists in reference to the question of vivisection, and other investigations demanding the destruction of the lower animals.

One-sixth of the annual deaths among the population in Iceland are solely owing to the Echinococcus entozoon, and shall we therefore refuse to permit the helminthologist to continue his experimental inquiries on the score of cruelty to animals? As a shrewd writer in the pages of the Examiner has recently very justly remarked, we have now arrived at a time when "every abomination has its zealous and thorough-going advocate."

The little entozoon producing the disease referred to has this singular peculiarity about it, namely, that in the adult or mature condition it scarcely attains a length of one-sixth of an inch, whilst in the larval, imperfectly developed, or so called hydatid condition, it may grow to the size of a man's hat. In the adult state it is a minute tapeworm, with four joints, and a single head, armed with four suckers, and a double crown of hooks; whereas, in the larval condition, it presents an aspect not unlike those toy air-balls which children play with. This globular hydatid is furnished with hundreds, nay thousands, of heads, each one of which is capable, under favourable circumstances, of becoming a tapeworm. The adult worm, as we have said, lives in the intestines of the dog, whilst the death-producing larva infests man and herbivorous animals of the domesticated kind.

To render our description more suggestive, we beg to direct

attention to the accompanying plate, for which we are indebted to Dr. Cobbold, who is at the present time engaged in preparing a new work on the entozoa of man and animals. He has also supplied us with the following explanatory references, which supersede the necessity of our entering into a more minute description of the worm. This entozoon will, doubtless, be more fully described in his forthcoming work:

EXPLANATION OF PLATE.-Fig. 1. Juvenile echinococcushydatid, about six weeks old (x 50 diam.). From a specimen reared by Leuckart, and now in Dr. Cobbold's collection. 2. Portion of a large Echinococcus hydatid from a cyst in the human liver. From a specimen in the Museum of the Middlesex Hospital, Dr. Murchison's case. Coloured naturally by the bile. 3. Similar portion of an hydatid, artificially coloured with magenta. Dr. Greenhow's case. Specimen preserved in the same museum. 4. Echinococcus-scolex, or head with the hooks and suckers displayed, from a zebra (× about 500 diam.). After Huxley. 5. Two of the hooks separated; one seen in profile, the other in front. After Huxley. 6. An entire sexually mature Taenia echinococcus, shewing the head, rostellum, suckers, and the three succeeding segments, the last of which is the largest, and contains the ova and other reproductive elements (30 diam.). From a specimen prepared by Leuckart, and now preserved in Dr. Cobbold's cabinet.

Having said thus much about the entozoon, and the disease it produces, one naturally desires to know what methods are to be adopted in order to quit ourselves of these ugly little customers. In the present state of our science we are not, perhaps, entirely able to bring about the total abolition of this terrible hydatid disease, but, at all events, the suggestions of Drs. Leuckart and Cobbold show us the way in which we may check it to a very noteworthy extent. We shall, therefore, allow these gentlemen to speak for themselves :

"In order to escape the dangers of infection, the dog must be watched, not only within the house, but whilst he is outside of it. He must not be allowed to visit either slaughter-houses or knackeries, and care must be taken that neither the offals nor hydatids found in such places are accessible to him. In this matter the sanitary inspector has many important duties to perform. The carelessness with which these offals have hitherto been disposed of, or even purposely given to the dog, must no longer be permitted, if the welfare of the digestive organs of mankind are to be considered. What blessed results may follow from these precautions may be readily gathered from the consideration of the fact that, at present, almost the sixth part of all the inhabitants annually dying in Iceland, fall victims to the echinococcus epidemic. It is true, that nowhere