63 



missioD, from sire or dam to the offspring, of defective tenden- 

 cies is, no doubt, responsible for the appearances of periodic 

 cpthalmia in certain families when the original blood was 

 so contaminated. In France the government discourages, 

 and prohibits when possible, the use of blind stallions or 

 mares for breeding purposes. The farmers and stockmen of 

 the country have observed and noted the influence of hered- 

 ity in the production of moonbliu Iness. From the replies 

 to a circular letter which I sent to farmers and stockmen in 

 all the counties of Alabama, twenty-one stated that heredity 

 was a primary or secondary factor in the cause of periodic 

 opt halm ia. 



Poor or badly ventilated and improperly lighted stalls or 

 barns are also causal factors. Prof. Williams of Edinburgh 

 says: "Fifty years ago thousands of horses became annually 

 blind from opthalmia; now-a-days one seldom sees a case of 

 blindness from this cause. This happy result is due to the 

 enlightened writings of Coleman on ventilation and the ad- 

 vance of veterinary science — facts which the public seem to 

 ignore." In improperly lighted stalls or barns the light is 

 so weak, or small in quantity, that the eyes are continually 

 strained in order to see distinctly ; or the light enters from 

 a small window^ directly in front of the horse, placing the 

 horse on the shady side of the objects in front of him, and 

 this in combination, or contrast, w-ith the constant glare of 

 the window, is certainly as trying on the eyes as insufficient 

 light. The light should come from behind or from either 

 side of the animal in quantity sufficient to make all objects 

 in the stall distinctly visible. It has been suggested that 

 exposure to cold, or to any of the atmospheric influences* 

 which ordinarily produce acute catarrh or cold in the head, 

 will cause an attack of moonblindness. The records of the 

 disease in the German army show that more cases occur in 

 winter than during any other season. But in this State the 

 majority of cases appear in the spring and summer. 



