VESICULAR STOMATITIS OF HORSES AND CATTLE. 5 



tion that the animal is sick. Owing to the painful condition of the 

 mouth at this stage, there is loss of appetite or at least inability 

 to eat, and in horses gritting of the teeth is quite frequent, while 

 in cattle ''smacking" noises are heard as in foot-and-mouth disease. 

 This sensitiveness as a rule remains for several days, after which 

 healing commences, and it is remarkable to observe how quickly 

 the sick animals will begin to eat even while their tongues are still 

 eroded. Although eating well, they do not regain their original 

 thrifty appearance for some time longer. In dairy cows in addition to 

 shrinkage in flesh there is a noticeable reduction in the normal 

 flow of milk for a few days. 



So far as our observations are concerned, the period of incubation 

 of vesicular stomatitis has varied from 36 hours to 9 days, but the 

 greatest number of cases have occurred in from 2 to 5 days after 

 exposure. 



No losses have been reported from uncomplicated cases of this 

 disease in either horses, mules, or cattle. A certain proportion of 

 horses and mules having vesicular stomatitis also became infected 

 with either influenza or contagious pneumonia, or perhaps both, and 

 some deaths have occurred among such animals. 



CONTAGIOUSNESS. 



That the malady is contagious has been definitely shown by the 

 transmission of the disease from sick to healthy animals by inoculation. 

 The degree of contagiousness, however, varies between wide limits. 

 In fact, certain writers have claimed that it is not contagious, because 

 they fail to reproduce the disease after experimenting with only one 

 healthy animal. Our experience with this disease shows that fre- 

 quently one or even more of the inoculated animals in an experiment 

 will fail to develop the infection, as in several instances we have 

 produced the disease in only two out of three, or two out of four, or, 

 again, three out of nine of the experimental animals; so that it is 

 necessary to use more than one animal if accurate information is to be 

 obtained. This point is strongly brought out by the opposite 

 conclusions reached by the two French investigators, Jacoulet and 

 Vigel, who recently found the disease in American horses shipped to 

 France. The former believes the disease is benign, nontransmissible, 

 and of alimentary origin, while the latter readily transmitted the 

 disease to other horses and convinced himself of its contagiousness. 



Experiments have proved that the disease is most virulent at 

 the time the blisters rupture or shortly thereafter, but when the 

 lesions are five or six days old the virus of the disease has practically 

 disappeared. This may account for the greatly differing results 

 investigators have had in their attempts to transfer the disease 

 artificially. These facts show the necessity of using several experi- 



