338 



Swine-Fever. 



[august, 



membrane on the inner surface of the intestines. The most 

 typical lesion is the swine-fever ulcer, which is most 

 commonly found in the large bowel about the junction of 

 the ileum and caecum, but swine -fever ulcers may also be 

 found much more rarely in the throat, on the tongue, and on 

 the skin. In examining the intestines of sick animals which 

 have been killed for purposes of diagnosis, it must be borne 

 in mind that it does not follow that the disease is not swine- 

 fever because the more typical lesions of ulceration and 

 diphtheritic deposit are not found. The experimental 

 inquiries conducted by the Board have shown that many 

 animals may have a slight attack of swine-fever and 

 recover in a little more than ten days. If cases of this 

 ■description be examined in the febrile stage, nothing more 

 may be found in the bowel than slight redness or abrasions 

 on the folds of the mucous membrane. The most common 

 form of ulcer is about the size of a threepenny piece. Its 

 edges are circular, and raised above the membrane. Its 

 •centre is soft and either yellow or black in colour. Con- 

 gestion of the mucous membrane of the bowel should always 

 be looked upon with suspicion, and particularly if it is combined 

 with inflammatory lesions in the lungs. 



Virulent Material and Spread of Injection. — It may be said 

 that the blood of pigs affected with swine-fever contains the 

 ■virus of the disease, since it has been proved to be capable of 

 infecting healthy pigs when injected under the skin. Since 

 the blood flows through all the organs during life they must all 

 be held to possess some degree of virulence. The intestines 

 containing lesions are particularly virulent, and it has been 

 shown repeatedly that swine-fever can be produced in healthy 

 pigs with great certainty by feeding them on diseased intestines. 

 The faeces of affected swine are also virulent. In practice the 

 •disease is spread mainly by the excretions from the bowels 

 of affected pigs. It is highly probable that infected faeces 

 are frequently carried from infected sties or premises to clean 

 ones on the boots or clothes of attendants or castrators. 



Prevention. — It may be stated at the outset that the more 

 -sanitary the condition of the premises, the less difficult it will 

 be to prevent swine-fever, once it is introduced, from spreading 

 all through the sties ; but for those who are compelled to 



