A study of the anatomical structure of worms, their physiological phenomena, and natural history is highly interesting, and productive of valuable results; still those considerations which relate directly to diseased states in consequence of their presence, will be of far greater practical importance to the reader.

Dr. Cobbold in his able and exhaustive treatise on "The Internal Parasites of our Domesticated Animals" states, "when people speak of worms in the dog, they commonly refer to round and tape worms; and in place of recognizing as they might, fully a score or more of intestinal parasites, they are content to roll the entire series into three or four species only. Thus, of the so-called lumbricoid and filariform worms, we have no less than eight or nine distinct forms, and of these the most common species is the marginated round worm".

In the recognition and treatment of disorders consequent upon worms it would seem wiser to leave the scientific study to zoologists and specialists, and to avoid confusion to reduce the classification in this work to the limit of practicability.

Probably no known disorder the dog is heir to is so destructive as intestinal worms, it being estimated by reliable authorities, that at least three fourths of the whole canine race are infected by the pest.

Among the many different species of internal parasites some are found in the liver, others in the eye; the giant strongle although rare, has been known to infest the kidneys; the wrinkled thread-worm sometimes reaches the bladder; the cruel thread-worm selects the heart, death resulting suddenly in a convulsion, or deferred for a time, during which the dog is racked by agonizing pain; in the nasal cavities and even in the blood and muscular tissues, parasites have been found.

These facts are of interest but of little practical importance, and it is by far more essential to consider those which are developed in the stomach and intestines.