PARASITOLOGY. 175 
Description.—This worm is flat and ribbon shaped, 
with a narrow neck of medium length joining the 
head to the body; the head is small and provided 
with four sucker discs. It is the unarmed tapeworm 
of man. The latter segments are a little longer than 
broad; the terminal segments are about three-six- 
teenths of an inch wide; the genital pores irregu- 
larly alternate. The worm may reach the length of 
forty feet. 
Life Cycle.—The life cycle is similar to that of the 
Taenia Solium. The intermediate host is the ox, 
which becomes infested through water or food contam- 
inated with the infested excrements of man. The 
ovum upon reaching the stomach of the ox is hatched 
into a microscopic globular-shaped embryo provided 
with six hooklets. Like the embryo of the preceding 
species they penetrate the tissues, through which they 
gradually work their way to various parts of the 
body, and in the course of nine days become station- 
ary and they form a cyst through the same trans- 
formation as in the preceding, which requires about 
sixty days. These cvsts are about two-thirds the 
size of a navy bean and contain a single larva which 
consists of ahead and neck. The head is provided 
with four sucker discs; by examining the cyst the 
larva appears as a small white mass attached to the 
mother or germinal membrane, floating in a color- 
less fluid, and plainly visible through the cyst wall. 
Should a member of the human family eat meat 
(beef dried, rare done or raw,) containing the cysts 
in which is found the living larva, he would become 
infested with adult tapeworm. In the stomach the 
larva would be liberated and upon reaching the 
