220 DADD'S VETERINARY MEDICINE AND SURGERY. 
beings were, at some time or other, created. Geology proves tira 
successive genera and species have been thus created, at long in- 
tervals apart; and the history of disease renders it probable that 
one affection, at least (syphilis), which is only propagated by direct 
descent, ex ovo, as it were, is really of comparatively recent origin, 
In conclusion, after the review of the preceding outline of an 
argument upon the generation of parasitic entozoa, we feel obliged 
to admit that the weight of facts and probabilities is wholly on 
the side of the doctrine of spontaneous generation. At the same 
time, we can not but look with interest to the results of future 
observations in this field, nor altogether suppress the hope that 
the simple law of Nature, omne vivwm ex ovo, may even yet be 
found to embrace the classes which now appear to form so striking 
an exception to its provisions,”’* 
Symptoms.—The usual symptoms indicating the presence of 
wornis in the intestinal canal are, sometimes, a scurfy, yellow mu- 
cous accumulation around the margin of the anus; the appetite 
is not uniform; the bowels are irregular, sometimes loose, and 
sometimes constipated; and the feces are often shrouded with 
shreds of mucus, of a yellow color. When ascarides are present 
(located in the rectum), the horse is much inclined to rub his tail 
against any post or fence he can get at, and he employs himself 
at such feats against the sides of the stall, in view, probably, of 
allaying the intolerable itching which usually attends the presence 
of these parasites. 
The lumbrici, or round worms, sometimes exist in the inutes- 
tines in great numbers. They are then apt to be hurtful. In 
such cases, the coat looks unthrifty, and the hair has lost its na- 
tural glossiness, and appears rough to the sense of touch. It has 
been noticed, also, that when horses are afflicted with intestinal 
parasites, their breath gives out a fetid odor, and they have a sort 
of dry, hacking cough. It is well known, however, that some 
horses, enjoying, apparently, the very best kind of health, are often 
the subjects of worms. 
Treatment.—Most of the remedies recommended in the ancient 
works on farriery are just about as likely to kill the horse as the 
parasites, and :onsequently are, to say the least, unsafe. The true 
theory is thi: worms are the result of indigestion; hence our 
* Stillé’s “ Elements of Pathology.” 
