SECTION XII. 
INTERNAL PARASITES. 
CHAPTER I. 
INTRODUCTORY. 
An exhaustive treatise on the subject of internal parasites or worms might 
interest some, but not the average reader, to whom solid facts only are impor- 
tant and of special value, such being quite sufficient to enable him to discrim- 
inate between the various common forms of these troublesome invaders, effect 
their expulsion, and recognize and properly treat the disorders to which they 
give rise. 
There are many different species of worms; and although the largest pro- 
portion of them abide in the intestines, some go deeper and lodge in the liver, 
others in the eyes; while the nasal cavities, lungs, bladder, kidneys, heart, brain, 
and even the blood, spinal chord, muscular tissues, and serous membranes have 
their special inflictions in the way of parasites, which exhibit a decided prefer- 
ence forthem. For instance, the giant strongle seeks the kidneys, the wrinkled 
thread-worm the bladder, and the cruel thread-worm the heart. Indeed, every 
important organ or structure of the body may be invaded by these often fatal 
pests. But, fortunately, dogs are not frequent victims of parasites which pene- 
trate very deeply ; moreover, when one has done so the fact is scarcely determi- 
nable; nor could aught be accomplished by treatment; therefore for practical 
purposes it can only be necessary to consider herein those which are often 
encountered and have their habitat in the stomach or intestines. 
OXYURIS VERMICULARIS. 
Thread-worms are silvery white in color, of small size, the largest being 
but little over one-half an inch in length, and have the appearance of small 
white threads; hence their name. 
They are located in the lower part of the intestinal canal,—the so-called 
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