220 DADDS VETERINARY MEDICINE AND SURGERI. 



beings were, at some time or other, created. Geology proves 1 hat 

 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 viviim ex ovo, may even yet be 

 found to embrace the classes which now appear to form so striking 

 an exception to its provisions."* 



Symj-jtoms. — The usual symptoms indicating the presence of 

 worms in the intestinal canal are, sometimes, a scurfy, yellow mu- 

 cous accumulation around the margin of the anus ; the a}>petite 

 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 iiites- 

 tines in great numbers. They are then apt to be hurtful. In 

 8uch 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. 



Ti'eatment. — Most of the remedies recommended in the ancient 

 works on fariery are just about as likely to kill the horse as the 

 parasites, and i^nsequently are, to say the least, unsafe. The true 

 theory is thl . worms are the result of indigestion; hence our 



*Still(^'8 "Elements of Pathology." 



