THE RAY- WORM. 539 



piece of wood or pasteboard, rolls the projecting end of the worm round it, and, after very 

 cautiously drawing it out for a few inches, he winds up the loosened portion, and ties the stick 

 close to the limb. Next day, he draws out a little more of the worm, and proceeds in a simi- 

 lar manner, until, in a fortnight or three weeks, the entire entozoon has been withdrawn and 

 wound upon the roller. 



This process is extremely simple, but demands the greatest care, as, if the worm should 

 be broken, a most painful and even dangerous tumor is certain to arise. I have seen a moder- 

 ately large specimen of the Guinea Worm extracted from an English sailor, into whose leg it 

 had made an entrance, and who was quite incapable of work until his enemy had been 

 destroyed. It is rather flat, like some kinds of silken thread, and is of a very pale brown 

 color. 



Passing by a few genera, such as Ascaris, Tricocephalus, and Strongylus, all of which are 

 found in the human subject, we come to the large and important genus Tsenia, which may be 

 accepted as the type of all the Entozoa. The well-known Tape-worm (Tcenia solium) belongs 

 to this genus. It derives its name of solium, as also its French title of Ver Solitaire, from the 

 supposed fact, that only one individual can infest the same person. It is, however, known 

 that a few cases have occurred where the same individual has been afflicted with at least two 

 specimens of Tape-worms. Those which belong to this genus may be known by the long, flat 

 body, and the head with four suctorial spots, and almost invariably a circle of very small but 

 very sharp hooks. The whole structure of the Taenia is interesting to those who study com- 

 parative anatomy, but too purely scientific to be described in these pages. 



Another species of Tape-worm that is found in the common cat is termed Tcenia crassi- 

 collis. An example of a Tape-worm that is found in several birds, such as the nightingale, 

 blackcap, and the lark, is called, after the last-mentioned bird, Lark-worm (Tcenia platy- 

 cephala). Another species of this is found in the black-backed gull. 



Tcenia, Tape-worm, is a parasitic worm of flattened, tape-like form, living in the intes- 

 tines of man and many of the lower animals. The long, tape-like creature is made up of many 

 joined together, each joint being regarded as a distinct animal. 



The Tcenia solium is the more familiar form. In a tolerably healthy person it may remain 

 parasitic during a long period. 



The treatment for this pest is aimed to dislodge the head ; for, if that is left, though all 

 of the body, its numerous joints, be thrown off, the head is a nucleus or starting-point for 

 more, and the disease becomes as troublesome as before. Once the head is dislodged, there is 

 an end of the creature. Pomegranate root and the extract of the root of the male fern are 

 regarded as the most efficient remedies. 



There is another notable genus of Entozoa, commonly going by the name of Hydatids, on 

 account of the large amount of . liquid which is found within their cells. Within each large 

 cyst, or cell, myriads of smaller cysts may be found, some in an early stage of progress, and 

 others being further advanced, and containing other cysts within themselves. 



I have seen some enormous Hydatids taken from the interior of a female monkey. They 

 were so large and so full, that the owner of the animal thought that it had died from over- 

 eating itself. On opening the creature, however, the stomach was found to contain very little 

 food, and almost the whole cavity of the chest and abdomen was filled with huge cysts, which 

 had encroached upon all the vital organs, pushed the heart on one side, enveloped the whole of 

 one lung, and, in fact, had caused so strange a disturbance of the viscera, that the fact of the 

 creature having supported life under such circumstances seemed almost incredible. The large 

 cysts contained a vast number of smaller cells, and these again were filled with cysts of still 

 less dimensions. A large quantity of fluid also existed, and floating in the liquid were found 

 myriads of echinococci, very small, but with the characters exhibited perfectly well under the 

 microscope. 



WE now come to our last examples of the Entozoa. 



The RAY-WORM is, as its name imports, an inhabitant of fishes belonging to the ray tribe. 

 The genus to which this creature belongs is a rather remarkable one, the head affording some 



