272 



Its causes may be fundamentally attributed to soil. On damp clays 

 and marshy grounds, on the frequently overflowed river bottoms and 

 deltas, on the coasts of seas and lakes alternately submerged and ex- 

 posed, this disease prevails extensively, and in many instances in 

 France (Reynal), Belgium, Alsace (Zundel Miltenberger), Germany, 

 and England it has wery largely decreased under land drainage and 

 improved methods of culture. Other influences, more or less asso- 

 ciated with such soil, are potent causative factors. Thus damp air 

 and a cloudy, wet climate, so constantly associated with wet lands, 

 are universally charged with causing the disease. These act on the 

 animal body to produce a lymphatic constitution with an excess of 

 connective tissue, bones, and muscles of coarse oj)en texture, thick 

 skins and gummy legs covered with a profusion of long hair. Hence 

 the heavy horses of Belgium and southwestern France have suffered 

 severel}'^ from the affection, while high dry lands adjacent, like Cata- 

 lonia, in Spain, and Dauphiuy Provence, and Languedoc, in France, 

 have in the main escaped. 



The rank aqueous fodders grown on such soils are other causes, 

 but these again are calculated to undermine the characters of the 

 nervous and sanguineous temperament, and to superinduce the lym- 

 phatic. Other foods act by leading to constipation and other disor- 

 ders of the digestive organs, thus impairing the general health ; hence 

 in any animal predisposed to this disease, heating, starchy foods, such 

 as maize, wheat, and buckwheat, are to.be carefully avoided. It has 

 been widely charged that beans, peas, vetches, and other leguminosa 

 are dangerous, but a fuller inquiry contradicts this. If these are well 

 grown they invigorate and fortify the system, while like any other 

 fodder if grown rank, aqueous, and deficient in assimilable principles 

 they tend to lower the health and oi^en the way for the disease. 



The period of dentition and training is a fertile exciting cause, for 

 though the malady may appear at any time from birth to old age, 

 yet the great majority of victims are from two to six years old, and if 

 a horse escapes the affection till after six there is a reasonable hope 

 that he will continue to resist it. The irritation about the head dur- 

 ing the eruption of the teeth, and while fretting in the unwonted 

 bridle and collar, the stimulating grain diet, and the close air of the 

 stable all combine to rouse the latent tendency to disease in the eye, 

 while direct injuries by bridle, whip, or hay-seeds are not without 

 their influence. 



In the same way local irritants like dust, severe rain and snow 

 storms, smoke, and acrid vapors are contributing causes. 



It is evident, however, that no one of these is sufficient of itself to 

 produce the disease, and it has been alleged that the true cause is a 

 microbe, or the irritant products of a microbe, which is harbored in 

 the marshy soil. The prevalence of the disease on the same damp 

 soils which produce ague in man and anthrax in cattle has been 



