ECZEMA CONTAGIOSA. 189 



degrees ; by the formation of vesicles, varying in size from that 

 of a sixpence to that of half-a-crown, on the tongue, inside the 

 lips, roof of the mouth, and sometimes on the udder; whilst 

 smaller blisters make their appearance between the digits, and 

 around the coronets and heels, and there is a discharge from 

 the eyes and nose. The animal presents signs of uneasiness in 

 the mouth, by constant movement of the lips, champing of the 

 teeth, a flow of saliva from the mouth, and difficulty in masti- 

 cating its food ; the affection of the feet being indicated by some 

 degree of lameness in the foot or feet affected. In a short time 

 the epithelial and cutaneous structures enclosing the vesicles are 

 separated and thrown off in more or less rounded patches 

 leaving raw surfaces (see Plate VI., p. 182), which are, however, 

 speedily re-covered by epithelium. In some instances there is 

 an entire separation of the hoofs from the feet. 



The symptoms are undoubtedly due to the presence of a conta- 

 gious micrococcus in the animal economy, and are manifestations 

 of the elimination or excretion of a virus, which evidently has 

 some special affinity to the mucous and cutaneous structures of the 

 several parts of the body which it invades. Eliminated by the 

 feet and by the mouth, pastures very soon become impregnated 

 with it, and hence we find that, owing to the great facility by 

 which it is thus spread over a wide district of country, it appears 

 to be the most infectious of maladies. Beyond question the 

 virus of eczema is conveyed from field to field, from parish to 

 parish, from county to county, by small game, vermin, and dogs ; 

 and looking to this fact, we can account for the sometimes 

 mysterious outbreak of the disease in places and districts into 

 which no fresh cattle have been admitted. This frequently un- 

 accountable appearance of the foot-and-mouth disease has led to 

 the belief that it is of spontaneous origin ; some believing that, 

 although originating spontaneously, it is propagated by contagion; 

 others that it originates in all cases independently of contagion, 

 and that it is due to climatic or atmospheric causes, exposure, 

 and the debilitating effects of long journeys by land or sea. It 

 is very true that increased susceptibility to the disease is in- 

 duced by any debilitating cause, but neither age, condition, 

 management, climate, temperature, nor any common cause of 

 disease seems to exert any modifying influence. No extremity 

 of privation, nor the continued action of ordinary causes, is 



