RABIES 565 



specific for the disease; they are found in other infections, especially 

 erysipelas, sepsis, pneumonia and tonsillitis. They are more likely 

 to be found in disease with which the streptococcus is associated. 

 Diagnostically they possess some value. If they are not found in a 

 doubtful case which has a rash and a marked fever, the case is prob- 

 ably not one of scarlet fever. 1 



Rabies. Rabies is a disease primarily observed among the carnivora 

 dogs, wolves and cats but it is transmissible to horses and to man. 

 Laboratory animals are readily infected with the virus. The saliva 

 of rabid animals is infectious and the natural mode of inoculation is 

 through bites of infected animals. The disease is also readily trans- 

 missible in an experimental way through the injection of emulsions 

 of the cord or brain of rabid animals directly into the central nervous 

 system of other animals. The infectious nature of rabies was first 

 clearly shown by Pasteur, Chamberland and Roux. 2 



The incubation period for "street rabies" is, on the average, from 

 one to two months, but it may be considerably longer. The incidence 

 of the disease among those bitten by rabid dogs depends largely upon 

 the location of the bite if upon the body protected with several 

 layers of clothing, infection may fail to develop; the virus is held 

 back by the clothing and fails to enter the wound. In general the 

 inoculation period is shortest when the hands or face are attacked, 

 because the virus acts upon the central nervous system and reaches 

 it through the peripheral nerves. 



The disease in man is practically always acute and death usually 

 terminates the infection within three to six days after the onset of 

 the symptoms. The initial symptoms are premonitory and consist 

 typically of slight irritation at the site of inoculation, together with 

 psychic depression. The characteristic symptoms are paralysis of 

 the muscles of deglutition which leads to extreme difficulty in 

 swallowing hyperesthesia, extreme restlessness and irritability, and 

 violent reflex spasms. Even so slight an effort as that required to 

 swallow water frequently causes such violent paroxysms that the 

 mere sight of water is distressing hence the name hydrophobia the 

 dread of water. It is important to remember that the hydrophobic 

 phenomena are much less commonly seen in rabid dogs than in man; 

 indeed rabid dogs frequently swim across streams that they happen 

 to encounter. The final stage of rabies is a progressive paralysis, 



1 Hill, loc. cit. 



2 Compt. rend. Acad. Sc., 1881. xcii, 159. 



