SCO ANNUAL OF SCIENTIFIC DISCOVERY. 



orpins of man, but more frequently in the liver and lungs of our domesti- 

 cated Ruminants, such as oxen, sheep, and goats. These hydatids are round- 

 isli bladders of milky-white color, containing a watery fluid, in which swim 

 many whitish granules; each of these granules is, as a good lens will show, 

 a well-developed head and neck of a Tania, inverted into a little bag. This 

 kind of hydatid, also, has been considered as a distinct genus of intestinal 

 worms, and called Echinococcus. 



Again, a disease frequently occurs in the brain of sheep, producing vertigo 

 (German, Dreher, French, tounn's). This was ascertained, years ago, to be 

 caused by another sort of hydatid, appearing as a bladder, often of several 

 inches in diameter; and, as in Cysticercus and Echinococcus, filled with a 

 watery fluid. On the outside of these bladders are attached a number (often 

 hundreds) of tapeworm heads, all retractile into the inside of the bladder by 

 inversion like the finger of a glove. This hydatid was considered by zoolo- 

 gists as a third genus, called Ccenurus. 



These three genera, Cysticercus, Echinococcus, and Cccnurus, formed until 

 recently an order in the class of intestinal worms, called Cystica (bladder 

 worms, or vesicular worms). But we now know that all of this group are 

 merely larva? of tapeworms, and that the whole order of Cystica, being com- 

 posed of larva? of Cestoidea, must therefore be dropped from our zoological 

 system. 



This important discovery was made as follows : Ephraim Gotze, a German 

 clergyman and naturalist of the last century, had noticed a singular similar- 

 ity between the heads of some Cysticerci and those of some tapeworms. He 

 had particularly noticed this similarity between the tapeworm of the cat 

 ( Tcenfa crassicollis) and the Cysticercus w r hich is found in the liver of the rat 

 and mouse (Cysticercus fasciolaris). C. T. von Siebold, the most noted hel- 

 minthologist now living, had observed the same thing, and in 1848 had 

 already alluded to the possibility that all these Cystica might be nothing but 

 undeveloped or larval tapeworms. In his system, however, he still recog- 

 nized the Cystica as a distinct order of Helminths. 



In the year 18-51, F. Kiichenmeister first proved by experiment that a cer- 

 tain hydatid, when brought into a suitable place, is developed into a tape- 

 worm. He fed a dog with the hydatids ( Cysticercus pisiformis) found in the 

 mesentery of the hare, and on dissecting the dog, after a number of weeks, 

 found these C3 T sticerci alive in the small intestine. They had, however, lost 

 their tail-bladder, and the neck had begun to form the joints of a true tape- 

 worm, which worm had been long well-known as Ttenia serrata, and as 

 common in the dog. Now, one discovery followed another. Governments, 

 scientific institutions, and wealthy farmers furnished the money and animals 

 to carry on the experiments on a large scale. Siebold fed a dog with the 

 Echinococcus of the ox, and thus raised the Ttenia Echinococcus, Siebold. It 

 was also found in the same way that the Ccenurus from the brain of sheep 

 is the larvae of another Tcenia of the dog, Ttenia Ccenurus, Siebold. 



Now the question, whence does man get his tapeworm? was ready to be 

 answered. It had been observed that the hydatids of the hog, commonly 

 called "measles" (in the zoological system, Cysticercus Cellulose), have exactly 

 the same head as the common tapeworm of man ( Tcenia Solium, L.) ; and after 

 the experiments mentioned above, in relation to the different tapeworms of 

 dogs, a doubt could hardly exist that Cyslicercus Cdlulosce of the hog was the 

 larvae of the common human tapeworm ( Tcenia SoJfuin). Kiichenmeister, who 

 wished to make sure of the fact, made the experiment upon a criminal who was 



