PARASITOLOGY. 155 
may appear nearly round; the long axis is parallel 
with the muscle fiber; the cyst usually contains only 
one larva although as many as seven have been ob- 
served; in this cyst the parasite remains dormant until 
the animal is killed and the meat is eaten, or if not 
slaughtered for several months the cyst will undergo 
degeneration. Two kinds of degeneration are noted, 
fatty and calcareous; in a few months the cysts are 
usually observed to commence fatty degeneration; 
first there are noted a few fat globules at the polls; 
these gradually increase and the fat is set free and 
invades the whole cyst; at about the seventh month 
lime salts (carbonate and phosphate) begin to ap- 
pear; calcification is usually complete about the 
twentieth month; during this process the cyst gradu- 
ally becomes opaque until the outline of the larva 
can scarcely be seen. Birds prove unfavorable sub- 
jects for muscular trichinosis; they, however, de- 
velop the intestinal form. 
Animals Infested.—Man, hog, dog, rat and, experi- 
mentally, other animals. 
Parts Intested.—Adults infests the intestine; the 
larval form infests the muscle structures. 
Conditions Produced.—This parasite produces two 
form of trichinosis; the adult infests the intestinal 
tract and produces intestinal trichinosis; the worm 
lives about six weeks; the larva is found wandering 
in the tissues and, finally encysted, this form is 
muscular trichinosis. 
Symptoms. — Man: — Nausea, vomiting, diarrhoea 
and vertigo; elevation of temperature with acceler- 
ated pulse and respiration; great muscular pain dur- 
ing migration of the embryos; contraction of certain 
