92 BOARD OF AGRICULTURE. 
most common among the poorer classes of society, and espec- 
ially among those who associate most familiarly with dogs, 
Pesce 66. 
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they are by no means confined to them. Many men of great 
eminence and talent have likewise perished from the same 
cause. And, unfortunately, society is so constituted that no 
one can be certain of escaping so long as the parasites that 
produce the eggs exist in the dogs of every country. It is 
estimated that 500 persons die annually by this parasite in 
Great Britain. 
These tumors, in their simplest form, or when young, con- 
tain a roundish cyst or membranous sac, enclosing a watery 
fluid, as-shown in Figure 66, which represents of natural size 
a parasite of this kind from the human kidney. More fre- 
quently the cysts become compound by a process of budding, 
either upon the outside or inside, or both without and within 
the membrane of the original cyst, so that its size goes on in- 
creasing indefinitely, sometimes becoming as large as a child’s 
head, and often completely permeating and destroying the 
liver, lungs, or other organs. Thus the danger becomes con- 
stantly greater and greater by reason of the pressure upon 
and destruction of the adjacent organs. When the budding 
is external, it results in a cluster of secondary cysts, often a 
dozen or more, and sometimes hundreds, all more or less con- 
nected together (Figure 67). And each of the external second- 
ary or daughter cysts, may increase and multiply itself in the 
same way, thus, at times, producing many hundreds of other 
tertiary cysts or “ grand-daughter cysts.” By internal budding, 
Figure 66—Hydatid or echinococcus cyst, natural size. Hearth and Home, 
after Thudichum. ; 
Figure 67.—Secondary cysts from a tam an 
On a y Waitin day ue amor in phe ver, natural size. From 
