“TRICHINA SPIRALIS. ~ 9 
after a tame a deposition of calcareous matter takes place, and it 
presents a whitish appearance, which renders it visible to the naked 
eye, as shown in Fig. 1. 
Once safely enclosed within its cyst or capsule, the trichina is 
powerless for mischief. It does not multiply; it does not consume 
the substance of the muscle in which it is imbedded, and the un- 
conscious ‘‘host”* may harbor it for many years without being 
Fig. 5. 
aware of the fact. The life history of the trichina is thus contained 
in a cycle which includes at least two animals—the first being that 
in which the parasite is born, partially matured, and then enclosed 
in a living tomb, and the second that in which it is set free, and in 
which it becomes fully mature, propagates its species, and dies. 
Such being the life history of the trichine, we are now prepared 
to consider their origin and the modes of their distribution, together 
with the most effective methods of avoiding and destroying them. 
*In the language of writerson this subject, the “host” or “bearer” 
is the animal (human or other) that harbors the parasite. The parasite 
is called a “guest” when it lives at the expense of the host, and a 
is mop mate ” when it merely shares its dwelling without devouring its 
substance. 
