DIAGNOSIS OF RABIES 125 
VII 
DIAGNOSIS OF RABIES 
The laboratory diagnosis of rabies is restricted, for all prac- 
tical purposes, to three procedures; namely,’ 
1. Inoculation of experimental animals with the brain of the 
suspected case. 
2. The determination of the changes in the ganglia as 
described by Van Gehuchten and Nelis. 
3- The presence of Negri bodies. 
(1) In the animal inoculation method rabbits are to be pre- 
ferred, although guinea pigs may be used. The animals should 
be inoculated with the suspected brain, preferably subdurally, 
although intraocular and, intramuscular inoculation can not 
be entirely excluded. The diagnosis by this method is not 
recommended, except in (a) case of failure by the other 
methods, and (4) where a late determination will be of value. 
The subdural method of inoculation is, briefly stated, as follows: 
The brain of the suspected animal is removed with aseptic 
precautions as soon as possible after death. A small piece of 
the brain or spinal cord is placed in a sterile mortar and thor- 
oughly ground with a few cubic centimeters of sterilized water 
or bouillon. This forms the suspension to be injected. The 
hands of the operator and all instruments are carefully disin- 
fected. The rabbit is etherized, the hair clipped from the head 
between the eyes and ears, and the skin thoroughly washed and 
disinfected. A longitudinal incision is then made, the skin 
and subcutaneous tissue held back by means of a tenaculum, 
a crucial incision is made in the periosteum on one side of the 
median line to avoid hemorrhage from the longitudinal sinus, 
1 Report of Committee on Standard Methods for the Diagnosis of 
Rabies. Read before the Laboratory Section of the American Public 
Health Association, Milwaukee, September, 1910. 
