INFECTIOUS DISEASES OF CATTLE. 393 



vims on their clothing and transmit it on their hands when milking, 

 since the udder is occasionally the seat of the eruption. Milk in a raw 

 state may also transmit the disease to animals fed with it. 



The observations made by some veterinarians would lead us to sup- 

 pose that the virus is quite readily destroyed. It is claimed that stables 

 thoroughly cleaned become safe after drying for a short time. Hence 

 litter of all kinds, such as manure, soiled hay, and straw, may remain 

 infective for a longer time because they do not dry out. Other author- 

 ities maintain that the virus is quite tenacious and may live in stables 

 even as long as a year. They also state that animals which have passed 

 through the disease may be a source of infection for several months 

 after recovery. 



Symptoms. After a period of incubation, lasting from three to five 

 days and sometimes not longer than two days, the disease begins with 

 a fever. The temperature does not as a rule rise above 104 F. The 

 lining membrane of the mouth becomes reddened, the appetite is dimin- 

 ished, and rumination ceases. The mouth is usually kept closed and 

 the quantity of saliva is increased. A smacking sound is not infre- 

 quently made by the animal. These symptoms are chiefly due to the 

 pain accompanying the disease in the mouth. After two or three days 

 the eruption appears. This consists of small yellowish- white vesicles 

 or blisters, about as large as a hemp seed or a pea, on the gums and 

 inner surface of lips, the inside of the cheeks, the border and under 

 surface of the tongue. They may become half an inch or more in diam- 

 eter. In some cases the back of the tongue near the tip may be the 

 seat of large blisters. 



These vesicles burst soon after their appearance, sometimes on the 

 first day. More rarely they may persist two or three days if small. 

 After they have ruptured the grayish white membrane forming the 

 blister may remain attached for a day or more, or disappear speedily 

 and leave deeply reddened spots or erosions, which are very painful. 

 These exposed spots may soon become covered again with the normal 

 epithelium, or else bo converted into ulcers under unfavorable condi- 

 tions. In this stage the saliva forms in large quantities and hangs in 

 strings from the mouth. In eight to fourteen days the disease may 

 have entirely disappeared. 



In'addition to the changes going on in the mouth, one or more feet 

 may become diseased. The skin around the coronet and in the cleft 

 between the toes becomes hot and tender and may swell. Blisters ap- 

 pear in the inoutli, but they are speedily ruptured, and the inflamed, 

 exposed spots covered with a viscid substance (exudate). 



The disease may attack t tlu> udder in cows, or more particularly the 

 teats. Some authorities regard the udder disease merely as the result 

 of infection during milking. The vesieles are broken as they appear 

 by the hands of the milker, and the teats become covered with red- 

 dened spots deprived of the superficial layer of skin, and are very 



