DISEASES OF THE OX AND SHEEP. 189" 



rarely, even four times. However, it may be held as a fact 

 quite free from doubt that if a disease appears more than once, 

 it is, on the second occasion of its appearance, much less severe. 

 Further, although many adult animals have succumbed from 

 foot-and-mouth disease, it is not, as a rule, fatal amongst older 

 oxen and sheep. Again, oxen have it usually more severe than 

 it is in the case of sheep. The mortality is much higher in 

 voung animals, and the disease often assumes a very virulent 

 type among animals which are suckling. The virus may be 

 destroyed by means of the easily -procurable gas chlorine, and 

 also by other germicidal agents, and, indeed, disinfectants are 

 most potent in regard to the contagium of this disease. Chlorine 

 is a yellowish-coloured gas, and is set free when diluted sul- 

 phuric acid is added to a mixture of salt and the black powder, 

 dioxide of manganese. 



The disease does not manifest itself in an animal directly the 

 infection is taken, but, on the contrary, it remains latent for 

 from one to four days before giving rise to any appreciable 

 disturbance. Our readers are aware that there is similarly an 

 incubatory period, which varies in length in the case of other 

 specific fevers of man and animals, and we have already spoken 

 of that of pleuro-pneumonia. In the case of measles in human 

 kind it varies from seven to ten days. In small-pox the average 

 duration of the stage of incubation is twelve days. So rapid is 

 the spread of foot-and-mouth disease, owing to its great infectious- 

 ness, that even before any germ had been actually demonstrated 

 it was almost certain that it had no other actual cause. 



In the case of oxen affected with this malady, the temperature 

 rises from about 101 J degrees F. to about 105 degrees F., 

 the animal has fits of shivering, the appetite is lost, the bowels 

 are constipated as a rule, and the breath has an offensive smell. 

 After about two days in most cases, vesicles, varying in size 

 from that of a threepenny bit to that of a half-crown piece, 

 appear in patches on the lining membrane of the mouth, i.e. of 

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

 sometimes on the lips and on the schneiderian membrane, on 

 the digits, in the case of female animals on the swollen and red 

 teats, in which case the virus is sure to be communicated to the 

 milk during the process of milking. These blebs are generally 

 rounded or oblong, and are elevated above the level of the sur- 



