Sivint Jr'layuti. 49l> 



2. Inlected streams may communicate the disease to lierds below 

 the source of infection. Running streams are fertile agents in 

 spreading the disease. Under no circumstances should pigs be 

 allowed access to streams, since they foul the water with their 

 dejecta, and if suffering from disease they spread it along the course 

 of the streams below the point of entrance of infection. The bacillus 

 of swine plague can maintain its existence for some time in water. 

 It can maintain its existence with bacteria usually found in water for 

 perhaps a month. 



3. The virus luay be carried in feed, implements, and on the feet 

 and clothing of persons from infected herds and j)remises. Desic- 

 cation and sunlight are powerful natural agents in destroying all 

 germs, but nevertheless before such agents can complete their work 

 spread of disease is brought about by particles adhering to feed, 

 implements, and the boots and clothing of human beings. 



4. Winds, insects, birds and various animals may transport tlie 

 tlisease. Winds are capable of blowing about dust contaminated Avith 

 the virus, and in this way the food supply may become infected. 

 Insects and birds and various animals may carry from place to place 

 on their feet or feathers or hair the germs of the disease^ and thus 

 lead to infection being spread through their agency. Insects may 

 contaminate the food. The agency of insects, birds, and other 

 animals in spreading the disease is pei'haps remote, but nevertheless 

 cases occur where it is impossible to definitely settle upon tlie origin 

 of the outbreak, and therefore all possible means of spi*ead are worthy 

 of being noticed. 



liVOOULATIOX. 



Preventive inoculation methods are worthy of extended trial. The 

 inoculation of attenuated cultures prepared in a proper fashion would 

 seem so far to have furnished favourable results. By inoculating an 

 animal with attenuated virus it is expected to be protected against 

 disease. The wide prevalence and virulence of the disease, and the 

 difficulty of controlling it by quarantine, and other methods, urges us 

 to discover some preventive. Experiments in this direction are being 

 carried out, but it will take a long time to determine the efficacy of 

 the vaccine employed. 



That we should hope to succeed in controlling the disease by 

 vaccination methods is not without parallel examples. Vaccination 

 against small-pox is the most familiar, as well as the most successful, 

 example of this method of treatment. Diphtheria has now been 

 robbed of its terrors by the practice. Vaccination against anthrax 

 in sheep and cattle has now become a general practice, and vaccination 

 against blackleg in cattle has also been marked by considerable success. 



In swine plague, which also belongs to the microbic class of 

 diseases, it is opined that a tirst attack when survived confers some 

 protection against a future one, and in this direction of procuring an 

 effective vaccine an interesting field of research is thrown open. 



