TANIA, 339 
ing and biting. While endeavoring to find relief by the latter means he is 
quite sure to swallow some of the disturbing lice which hold the young 
embryos. Thus the latter are returned to and redeveloped into perfect tape- 
worms in the very intestinal canal which they left as eggs but a few weeks 
previous. Through this method of transmission an animal may continually 
reinfect himself, or by depositing in the kennel the lice containing the embryos, 
or shaking them from his coat into the drinking-water or food, they may be 
introduced into the bodies of other dogs; and they in turn become infected. 
Bothriocephalus latus, commonly known as the fish tape-worm, is the 
largest internal parasite which dogs harbor. But while they are not exempt 
from this infliction, fortunately they do not often suffer from it, their escape 
being, possibly, due to the fact that the kinds of food in which its embryos are 
very generally located are not popular with them; hence it is but seldom a 
part of their diet. It is rare in this country, and in Europe is common only 
in countries bordering on inland lakes and seas. The length attained is often 
from twenty to thirty feet. The head is almond-shape, and nearly one-twelfth 
BEEEEEPEEE 
Bothriocephalus Latus.—1. Portions of the worm, of natural size. 2. Head magnified. 
of an inch long; while its diameter is from one-fourth to one-sixth of an inch. 
The segments differ quite decidedly from those of other tape-worms, being 
much broader and shorter. The ova are also larger than those of the pork or 
beef tape-worms; but their shell-covering is thinner, and it has a sort of lid 
at one end. ‘They develop only in fresh water; and, swallowed by pike and 
other fish, change into cysticerci, in the muscles, peritoneum, and solid inter- 
nal organs. Evidently, therefore, man, the dog, and other victims take in the 
embryos while eating fish that is ‘‘ measly,” raw, or but only partially cooked. 
This tape-worm is a much greater tax upon the host than most parasites of its 
kind, and infested dogs very generally lose weight quite rapidly, and ere long 
are reduced to ‘‘skin and bones.” Fortunately, however, it is more easily 
removed than smaller and more delicate worms, for there is less liability of its 
being broken and the head left behind. 
Tenia Solium is also less often found in this country than in Europe. It 
ranges from six to thirteen feet in length. The head is of about pin-head size, 
rounded, and attached to a thread-like neck. This parasite develops in the 
small intestine, from embryos contained in raw or only partially cooked 
‘‘measly ” pork, consequently it is properly termed the pork tape-worm. The 
term solium would indicate that it invariably existed singly, but that is not so, 
