DISEASES OF THE DIGESTIVE ORGANS. 217 
is uot the case with the salivary glands and their products. The 
pancreatic juice may, like every other secretion, be found to con- 
tain adve-:titious substances that have accidentally entered the 
blood. Thus, iodide of potassium may be eliminated from the 
system by the pancreas. It is not so with every salt, the prussiate 
of potash, for example, never being seen in the pancreatic juice. 
The pancreatic secretion is formed during infra-uterine life, but 
we are at a loss to account for its uses there. It is difficult to de- 
termine what nervous influences affects its production. A dose of 
ether excites it, and pressure on the abdominal viscera likewise 
tends to its increase; the efforts of vomiting stop it.” 
WoRrRMS OR PARASITES WHICH INFEST THE INTESTINAL CANAL 
There are various forms of parasites which infest the alimentary 
canal of horses and cattle which, no doubt, are the cause of some 
annoyance to the infested ; but really they are not, at all times, so 
injurious as some writers make them out to be. They are rarely 
if ever found in the intestines of healthy animals, and their pres- 
ence is generally due to a deranged condition of the digestive 
organs. They very frequently originate spontaneously. 
“Certain independent organisms, both vegetable and animal, 
are found in the body. The vegetable growths are all microscopic, 
and belong to the lowest order of plants, the alge and fungi, 
They are never met with except upon cutaneous or mucous sur- 
faces, nor while these surfaces remain healthy, usually. A secre- 
tion of fibrine or mucus, undergoing decomposition, forms the soil 
in which they grow. In some cases, they are believed to be the 
media of contagion. 
Animal parasites are very numerous. Many of them are in- 
fusorial. Many belong to the class of insects and mites, as fleas, 
lice, bugs, and the acari, of which the most important one is the 
itch-mite. A class of higher consequence comprises several sorts 
of worms. Those which infest the intestinal canal are extremely 
eommon, and are the orguris vermicularis, or thread-worm, which 
inhabits the rectum; the trichocephalus dispar, or long thread- 
worm, which is found in the large intestine, and especially in the 
cecum ; the ascares lumbricedes, or round worm, whose ordinary 
residence is the small intestine; the tape-worm, or tenia, whicl 
also affects the same part. The kidney is occasionally the seat of 
