Rabies. 139 



ployed only with human beings, although animals could 

 be treated but the expense is too great. 



It is noteworthy that the protective treatment can be 

 applied in the case of rabies several days after the bite 

 is inflicted, an unusual condition with reference to im- 

 munization. On account of the time and expense con- 

 nected with the preventive treatment, it is desirable to 

 know with certainty that the suspected animal really has 

 rabies. This can be determined with certainty only by 

 keeping the dog that inflicted the bite under observation. 

 If the animal is rabid, a definite diagonsis can be made 

 from the symptoms, and death is certain to follow. If the 

 dog has bitten persons, it is especially desirable that it 

 should not be killed for the delay in determining whether 

 the animal was actually rabid or not may be sufficient to 

 allow the disease to make such headway that treatment 

 will be of no value in preventing the disease. Until re- 

 cently the diagnosis was made by the inoculation of a 

 portion of the spinal cord into rabbits. A more rapid 

 method is now employed, a definite portion of the brain 

 is examined microscopically and within twenty-four 

 hours the diagnosis can be made, while with the old 

 method at least two weeks were required. 



A very unsatisfactory condition in all methods of diag- 

 nosis in the laboratory exists. If the rabbits inoculated 

 succumb to rabies or if the peculiar bodies characteristic 

 of the disease are found in the brain of the suspected 

 animal, it is certain that rabies is present. If the bodies 

 are not found, it is not certain that the animal was free 

 from the disease. Again, the rabbits inoculated may not 

 die from the disease for a much longer period than the 

 average, so late, indeed, that preventive treatment may 

 be of no value, if it is not begun until the diagnosis is 



