360 HORSE, SWINE AND POULTRY DISEASES 



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 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, and vetches 

 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 princi- 

 ples, 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 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 

 quoted in support of this doctrine, as also the fact that the malady is 

 always more prevalent, other things being equal, 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 sew- 

 age being assumed to form a suitable nidus for the growth of the 

 germ. But on these sewage farms a fresh crop may be cut every fort- 

 night, and the product is precisely that aqueous material which con- 

 tributes to a lymphatic structure and a low tone of health. The 

 presence in the system of a definite germ has not yet been proven, and 

 in the present state of our knowledge we are only warranted in charg- 

 ing the disease to the deleterious emanations from the marshy soil in 

 which bacterial ferments are constantly producing them. 



Heredity is one of the most potent causes. This is notorious in 

 the case of both parents, male and female. The tendency appears to 

 be stronger, however, if either parent has already suffered. Thus a 

 mare may have borne a number of sound foals, and then fallen a vic- 

 tim to this malady, and all foals subsequently born have likewise 

 suffered. So with the stallion. Reynal even quotes the appearance 



