310 AGRICULTURAL BACTERIOLOGY 



reach the diameter of a dime or even larger. They rupture 

 soon after their appearance, leaving reddened sensitive 

 spots or erosions behind. Food is refused, and a ropy saliva 

 drools from the mouth. The soreness of the feet often ren- 

 ders it impossible for the animal to stand. 



The disease spreads with great rapidity in the herd. The 

 chance that all of the herd will acquire it has led to the 

 inoculation of the animals by the transfer of some of the 

 saliva from the diseased to the healthy animals, with the 

 idea of shortening the period of trouble in the herd. In 

 cases of doubt as to the nature of the disease, the inoculation 

 of a calf should give definite information, since the inocu- 

 lation should result in the characteristic vesicles in from 

 twenty-four to seventy-two hours. 



There are a number of diseases that somewhat resemble 

 foot-and-mouth disease. Cowpox forms similar vesicles, but 

 the inoculation does not result in symptoms of fever and 

 eruption for at least ten days. In mycotic stomatitis, or 

 inflammation of the membranes of the mouth, the entire 

 mouth cavity is inflamed and vesicles are rare; if present, 

 they do not increase in size. The thin skin between the 

 toes may be inflamed, but the vesicles do not appear, nor 

 is the udder affected. The disease does not spread and the 

 inoculation of calves is not successful. In foot-rot the in- 

 flammation of the foot is general, and the mouth remains 

 unaffected. In ergotism, or trouble due to the eating of 

 too great quantities of smut, the mouth is not affected, and 

 the tissue changes are to be noted at the tips of the ears, 

 end of the tail, and upon the lower part of the legs. 



Foot-and-mouth disease is transmitted to man by the use 

 of infected milk. It causes eruptions in the mouth and 

 on the fingers, but is seldom fatal, except in the case of 

 weakened children. In man it is known as aphthous fever. 



