80 DISEASES OF THE HOG. 
which are received into the alimentary canal are 
capable of development in a healthy state of this 
structure, as worms are sometimes found in the 
stomach and intestine of the hog. There are cer- 
tain conditions of these organs which are favor- 
able for the breeding of worms, such as indiges- 
tion, the accumulation of undigested food and of 
mucus and diseases of the intestine. The kind 
of food the animal eats in a raw condition contain- 
ing the ova of worms makes the pig more liable 
to worms than other animals. All kinds of vege- 
table and animal food should be cooked: grains 
can be eaten raw with impunity; hogs should 
not be allowed to eat diseased meat unless it has 
been thoroughly cooked. I have known healthy 
pigs which were given the flesh of animals that 
died from ‘disease to become badly affected with 
- worms. 
‘THORN-HEADED WORIIS. 
Figure 74. a 
Figure 74.—This worm is quite frequently found 
in the intestines of pigs; it is easily known by the 
peculiar proboscis which bears several circles of 
small but sharp hooks. They locate usually in the 
_ small intestines of the pig, where they fasten them- 
selves by means of the spiny proboscis mentioned 
above, this being pushed into the lining membrane 
of the intestine; in some cases they bore through 
