900 DISEASES CAUSED BY F1LTRABLE VIRUS 



RABIES 



(Hydrophobia, Rage, Lyssa, HundswutJi) 



Rabies is primarily a disease of animals, infectious for practically 

 all the mammalia, but most prevalent among carnivora, dogs, cats, 

 and wolves. It is said also to occur spontaneously among skunks 

 of the Southwestern United States, and is readily inoculable upon 

 guinea-pigs, rabbits, mice, rats, and certain birds, chicken and geese 

 being especially susceptible. Man is subject to the disease. Infec- 

 tion usually occurs as a consequence of the saliva of rabid animals 

 gaining entrance to wounds from bites or scratches. The disease 

 is more or less widely prevalent in all civilized countries except 

 England, where the careful supervision of dogs, enforcement of 

 muzzling laws, and rigid legislation regarding the importation 

 of dogs, have caused a practical eradication of the disease. 

 A fair estimate of the prevalence of the disease may be ob- 

 tained from the statistics - of animals dyin^ or killed because of 

 rabies in different countries. In Germany, according to Kolle and 

 Hetsch, during the fifteen years ending in 1901, there were 9,069 

 dogs, 1,664 cattle, 191 sheep, 110 horses, 175 hogs, 79 cats, 16 goats, 

 1 mule, and 1 fox affected with rabies. In eastern United States 

 the disease is not uncommon. The statistics of the New York 

 Department of Health, for a period of six months ending December 

 31, 1907, show seventy-four cases of rabies among dogs in New 

 York City and vicinity. Among human beings the disease is no 

 longer common in civilized countries, since early preventive treat- 

 ment is successfully applied in almost all infected subjects. 



Experimental infection in susceptible animals is best carried out 

 by injections of a salt-solution emulsion of the brain or spinal cord 

 of an afflicted animal, subdurally, through a trephined opening in 

 the skull, but may also be accomplished by injection into the per- 

 ipheral nerves, the spinal canal, or the anterior chamber of the eye, 

 Intravenous and intramuscular injections are also successful, though 

 less regularly so. 



The time of incubation after inoculation varies with the nature 

 of the virus used, the location of the injection, and the quantity 

 injected. In accidental infections of man and animals the incuba- 

 tion is shortest and the disease most severe when the wounds are 



