EPIZOOTIC APHTHA. 269 



toms common to man and animals, and there are others 

 which are peculiar to each. 



a. The disease is invariably characterized by a brief 

 period of incubation, varying from 24 hours to three or 

 four days. It is ushered in by a shivering fit, and a vesi- 

 cular eruption occurs in the mouth and on the digits; in 

 female animals, usually also on the teats. There is a tendency 

 in young animals, especially such as are sucking or drinking 

 milk, to a similar eruption on the fauces and pharynx, with 

 irritation of the larynx and of the whole digestive tube. 

 Diarrhoea in these cases tends to exhaust the young animals 

 whose sore mouths prevent the taking of food. 



The eruption in the mouth is first indicated by smacking 

 of the lips, salivation, and loss of power from the prehension 

 and mastication of food. The pain is evidently intense, and 

 on opening the mouth vesicles are found about the size of a 

 bean or hazel-nut. They are sometimes congregated in 

 patches, on the inner surface of lips and cheeks, on the 

 tongue, and occasionally on the Schneiderian membrane. In 

 about 18 hours the vesicles burst, and the red painful spots 

 thus exposed are soon covered with epithelium in favourable 

 cases, whereas in others unhealthy ulcers develope. 



When the eruption occurs on the feet, it is observed 

 around the coronet and in the interdigital space of cloven- 

 footed animals. The intense pain indicated by inability to 

 stand, or lameness, and the swelling above the hoof, are 

 usually the first signs noticed. The vesicles which form 

 burst soon, in consequence of the animals' movements. The 

 vascular secreting structures of the whole foot may be so 

 inflamed as to lead to casting of the hoofs. 



When the eruption occurs on the mammae, the teats are 

 sore and swollen. Vesicles form as in the mouth. They are 

 large and well raised from the surface of the skin never 



