186 PARASITOLOGY. 
branes; the hydatic membrane is thick while the 
germinal membrane is thin. The cyst develops 
very slowly and arrives at this stage in about five 
months; on the inner surface of the mother mem- 
brane appears a minute papillary elevation which 
becomes hollowed in the center and forms another 
cyst called the daughter cyst (secondary or proliger- 
ous cyst). This is attached to the mother membrane 
by a short pedicle; the bud from the mother mem- 
brane may develop a larva or scolex which is attach- 
ed to it by a short slender pedicle; this development 
may proceed until fifteen or twenty heads are there 
attached; on the inner side of the daughter vesicle 
may be developed five to ten heads or larvae or 
another vesicle called a grand-daughter vesicle ; the 
grand-daughter vesicle may develop within it another 
cyst called a great-grand-daughter vesicle, whichis 
always an acephalocyst. These secondary cysts 
may develop so as to be practically outside of the 
mother cyst, thus, multiple cysts result. The cyst 
contains a colorless poisonous fluid of saline, neutral 
or slightly acid reaction; this development goes on 
until the entire organ is filled with multiple cysts; 
these cysts vary in size up to one and one-half 
inches in diameter. This condition is called echino- 
coccus veterinorum, echinococcus polymorphus, 
echinococcus granulosus or cysticercus echinococcus. 
Sometimes instead of this form of cyst formation there 
is formed a cluster of cysts varying in size from a mil- 
let seed to a pea; these are in clusters like a bunch of 
grapes and are called echinococcus multilocularis or 
echinococcus alveolaris. These cysts may undergo 
degeneration; the cyst wall ruptures and the cyst 
