140 BOARD OF AGRICULTURE. 
mant and enclosed in cysts, in which they pass a sort of 
pupa state. During this period of their life, the skin is cast 
several times, and the appearance changes at each moult, un- 
til they attain the next period of their life, when they 
again become active; thisis the state described as Petastoma 
denticlatum. These larve are long-oval, broadest anterior- 
ly, and covered with numerous rows of transverse tooth-like 
spinules. They have two pairs of sharp, curved claws, which 
are situated near the mouth and placed obliquely, diverging 
from the median line of the body, and directed downward. 
Each claw has a sort of hood or capsule, into which it can be 
retracted. If dogs feed on the liver or other viscera of animals 
containing these larve, they come in contact with, and man- 
age to enter the nose, working their way up by means of the 
motions of the body, aided by their spines and claws. In 
this situation they gradually become mature. 
In the human body the larval form is quite frequent, es- 
pecially in some parts of Europe ; but there is little known 
concerning the effects that it produces. When in small num- 
bers, it probably causes very little disturbance, but if in large 
numbers, in the liver and lungs, it would no doubt produce 
serious disease, as does another species (P. constrictum), 
which is very common in Egypt, living in the same way en- 
eysted in the liver and lungs. The latter, when in consider- 
able numbers, frequently proves fatal. - 
As a means of prevention, dogs that show symptoms of 
the parasites in the nose, should be treated to a solution of 
carbolic acid, thrown up the nostrils by a small syringe. 
Feeding dogs with the offal of slaughter houses, or with un- 
cooked livers, etc., should be avoided, both on account of this 
and the other dangerous parasites that they getin this way, 
(see Tenia echinococcus, p. 202, T. marginata, p. 192, T. 
cenurus, p. 196, and Zrichina spiralis, p. 222). Too much 
familiarity, especially of children, with dogs is always liable 
to result in the transfer of these and other parasites to the 
human body. 
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