292 DISEASES OF THE HOESE. 



with wet lands, are universally charged with causing the disease. 

 These act on the animal body to produce a lymphatic constitution 

 Tzith an excess of connective tissue, bones, and muscles of coarse, open 

 texture, thick skins, and gummy legs covered with a profusion of 

 long hair. Hence the heavy horses of Belgium and southwestern 

 France have suffered severely from the affection, while high, dry 

 lands adjacent, like Catalonia, in Spain, and Dauphiny, Provence, 

 and Languedoc. in Fiance, have in the main escaped. 



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

 these again are calculated to undermine the character of the nervous 

 and sanguineous temperament and to superinduce the hmiphatic. 

 Other feeds act by leading to constipation and other disorders of the 

 digestive organs, thus impairing the general health. Hence in any 

 animal joredisposed to this disease, heating, starchy feeds, such as 

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

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

 are dangerous, but a fuller inquiry contradicts the statement. If 

 these feeds 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 open 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 2 to 6 years old, and if a 

 horse escapes the affection till after 6 there is a reasonable hope that 

 he will continue to resist it. The irritation about the head during 

 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 contributmg 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 

 quoted in support of this doctrine, as also the fact that, other things 

 being equal, the malady is always more prevalent in basins sur- 

 rounded by hills where the air is still and such products are concen- 

 trated, and that a forest or simple belt of trees will, as in ague, at 

 times limit the area of its prevalence. Another argument for the 

 same view is found in the fact that on certain farms irrigated by 

 town sewage this malady has become extremely prevalent, the sewage 

 being assumed to form a suitable nidus for the growth of the germ. 



