INFECTIOUS DISEASES 299 



ulcer. As ulceration progresses, difficulty iu nursing increases 

 until finally the young animal is unable to suckle. If ulceration 

 of the mouth is extensive, the animal may be feverish, dull and 

 lose flesh rapidly. Portions of the lips, gums and snout may 

 slough off. The death-rate in pigs is very high. 



The preventive treatment consists in keeping the quarters 

 and yards in a sanitary condition, and using all possible precau- 

 tions against the introduction of the disease into the herd. The 

 diseased young and mother should be separated fi-om the herd 

 and the quarters disinfected daily. The 

 mouths of all the young should be ex- 

 amined daily and the diseased animals 

 treated. The ulcers should be scraped 

 or curetted and cauterized with lunar I 

 caustic, and the mouth washed daily 

 with a two per cent water solution of 

 a cresol disinfectant. Dipping pigs 

 headforemost into a water solution 



. , Fig. 104. — Bacillus necrophorus. 



01 permanganate oi potassium (one- 

 half teaspoonful dissolved in a gallon of water), twice daily, 

 may be practised if the herd is large. 



It is usually most economical to kill the badly diseased 

 animals, as they usually die or become badly stunted. 



Rabies, Hydrophobia. — Rabies is an infectious disease af- 

 fecting the nervous system, that is transmitted by the bite of a 

 rabid animal and the inoculation of the wound with the virus 

 present in the saliva. It is commonly considered a disease of 

 dogs, but because of the disposition of rabid dogs to bite other 

 animals, rabies is common in domestic animals and man. 



Eabies is widely distributed, being most prevalent in the 

 temperate zone, and where the population is most dense. It 

 has been excluded from Australia, Tasmania and New Zealand 

 by a rigid inspection and quarantine of all imported dogs. 



The specific cause of rabies is probably a protozoan para- 

 site (the Negri bodies present in nerve-cells, Fig. 105). The 



