TRICHINA 
177 
mammal. When pork, infected with this parasite and 
insufficiently cooked, is eaten by man the cysts are dissolved 
by the digestive fluids and the worms are freed. 
These worms then develop eggs and sperms which after 
uniting mature into young worms and migrate through the 
intestine into the muscles. The activity of the worms at 
this stage causes a serious inflammation of the tissues and a 
disease known as trichinosis (trik-m-o'sis), which is often 
fatal. Hogs contract trichino¬ 
sis by eating refuse that con¬ 
tains the encysted worms. 
Government inspectors ex¬ 
amine pork which is to be 
exported or sold in large 
quantities to see that it is free 
from these parasites. The 
smaller sales of pork by local 
dealers are not inspected and 
the only way to be sure of the 
harmlessness of the meat is to 
cook it thoroughly. 
Hair Worm. — The only im¬ 
portance that can be attached 
to these worms is the myth 
about their origin. In almost 
every school will be found students who believe that horse 
hairs placed in water will develop into “ hair snakes.” It 
would be a pity if a student still believed this after a course 
in biology. 
Let us see how such a belief can originate and often be 
thought to be proved. The hair snakes live for a time in 
water and often in the watering troughs where horse hairs are 
also found. Boys, and men too, sometimes put horse hairs 
in water and then after a few weeks examine the water and 
find these hair snakes. They conclude, since they put in the 
