340 KENNEL DISEASES. 
although usually the case. Man and the dog are its hosts, but the latter, in this 
country certainly, is of the two the most fortunate. The segments are con- 
stantly maturing and being expelled in the discharges from the bowels; and it 
has been estimated that were the head to remain in an intestine, as many as 
eight hundred segments would be developed and cast off by this worm before 
its reproductive power became extinct. Those segments are about two-fifths 
of an inch in length, and from one-fourth to one-third of an inch in breadth. 
Tenia Marginata is the largest of the various tape-worms which are common 
in dogs, and may attain a length of ten feet. Owing to quite a close resem- 
blance, it has often been confounded with the tenia serrata; yet it is a larger 
worm, and presents decided peculiarities about the head. The list of its vic- 
tims includes sheep, goats, and many other ruminants, also swine, monkeys, 
and squirrels. Man may be infested by it, but only while it is still in the im- 
mature or cysticercal condition. The larve of this worm are sometimes found 
in the livers of the animals mentioned, enclosed in cysts or sacs about the size 
of American walnuts; but they exhibit a decided preference for serous mem- 
1 2 
Tenia Solium.—1. Portions of the worm, of natural size. 2. The head magnified. 
branes. Evidently dogs having access to slaughter-houses are quite sure to 
soon become infested by this species of tape-worm; while the eggs scattered 
about by those dogs produce the so-called bladder-worm in the unfortunates 
who acquire them; and this often proves fatal because it cannot be reached by 
medicine. 
Tenia Saginata or Mediocanellata in general appearance somewhat resem- 
bles the solium, but the head is larger. The segments also are larger, thicker, 
and stronger. When matured it is from twelve to twenty feet long. The head, 
about one-twelfth of an inch in diameter, is flat, and, unlike the heads of most 
tape-worms, it has no hooklets, but possesses sucking disks only. This is a 
beef tape-worm, and infection is attributable to eating raw or only slightly 
cooked flesh of ruminating animals, as the ox, sheep, goat, etc., in the muscles 
of which the embryos are located. They are also to be found in some of the 
internal organs. After being detached the segments exhibit a crawling motion, 
which might lead to the supposition that they were individual parasites. Asa 
result of this peculiarity they often make their way out of the body; and the 
number of segments which thus pass spontaneously and are expelled in the 
discharges is very large, so rapid is the reproduction and growth. 
