63 



after the real exciting cause had established it, the corn either 

 maintained a supply of food for the microbe or diminished 

 the general vigor of the animal or the resisting power of the 

 leucocytes — germ destroying cells of the body. High feeding 

 associated with irregular exercise, feeding irregularly and 

 using unwholesome, decayed or partially rotten hay, fodder 

 or grain ; also the surface water of runs, ditches, ponds and 

 shallow wells receiving the impurities from barns, barn yards 

 or outhouses — all these are contributing causes and many 

 times the impure water may convey the microbe, the origi- 

 nating cause, into the system. 



Overworking an animal, no doubt, depresses the vigor and 

 resisting power of the animal; thus attacks are more liable 

 to begin or recur during the severe, exhausting spring plow- 

 ing and summer work. During the time of breaking the 

 colt and of the eruption of permanent teeth the attacks are 

 excited to greater severity and are called forth more fre- 

 quently. The eruptioa of nearly all the permanent teeth 

 occur during the last half of the third, fourth and fifth years 

 of age. The small teeth that usually appear just in front of 

 the first molar on either side of the upper jaw, very rarely 

 in lower jaw, are commonly called wolf teeth or "blind teeth." 

 Many people believe that this little tooth in some mysterious 

 way affects the eye, causes it to go blind "by pressing on the 

 nerve of the eye." This is, to say the least, very unreasona- 

 ble if not nonsensical. Those little teeth never affect the 

 eye. No doubt they are broken off many times when a horse 

 has an attack of periodic opthalmia and the eye "clears up" 

 in ten to fifteen days — not because the little tooth was pulled 

 or broken off with a punch — but because that eye disease 

 appears and disappears periodically. Heredity is certainly a 

 strong predisposing cause of the disease. It does not orig- 

 inate the disease but the offspring inherits the tendency or 

 weakness of the eyes, that permits the originating excitant 

 to call forth the disease with little resistance. This trans- 



