Licence: Public Domain Mark
Credit: Hydatid disease in New Zealand / by R. Gordon MacDonald. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![the eggs, which are scattered broadcast wherever infected dogs exist, and soon find their way into the food and drink of these animals. The warmth and moisture in the intestines of their new host are sufficient to dissolve the egg-capsule, and the young giant emerges to penetrate its unfortunate friend's bowels, and begin its destructive cystic life. The experiments made by Haubner and Leuckart on pigs disclose the fact that in four weeks from date of feeding, the young Echinococci can easily be seen as small tubercles on the surface of the liver and kidneys. Its rate of growth is very uncertain and irregular. Sometimes a number of years (ten or more) may elapse before it causes much annoyance to its new host. A good deal will doubtless depend upon the vitality of the egg, and the locality in which it fixes itself. Neisser is of opinion that the embryos are quite passive in their transmission through the tissues ; but Cobbold, Leuckart, and others state that they are by no means motion- less, and that they bore their way through the intestines to reach their final destination. Their internal wanderings may be effected through the bloodvessels or lymphatics, and this view is supported by the preference of the parasite for the liver, which is rendered easily accessible through the portal circula- tion. That all Echinococci are not found in the liver is easily accounted for by the circumstance that the embryos readily pass by the lymphatics into the venous system. The Echinococcus of man and other animals produces in the dog's intestines a similar worm to the one whose eggs infected them. Finsen, of Iceland (where this disease kills one-sixth of the population), made the following experiments:—He fed healthy dogs on liver containing Echinococci, and in 35 days the dogs passed large numbers of mature worms. The same results were obtained by giving dogs the hydatid fluid taken from the sac by means of tapping. From inquiries recently made by myself I find that rabbiters taking healthy dogs from the towns, and feeding them upon rabbits, soon begin to notice signs of uneasiness in them. In about a month they become very dry in the hair, and loose condition ; and in about six weeks ] large numbers of worms, which they evidently acquired from the rabbit Echinococcus. It is thus absolutely certain that the dog is the propagator of the disease, and that the mature worm is only to be found in the intestines of the dog. There is no](https://iiif.wellcomecollection.org/image/b21912002_0010.jp2/full/800%2C/0/default.jpg)
