DIAGNOSIS OF RABIES 77 



chamber in a plane parallel to the plane of the iris, when the aqueous 

 humour flows out. A few drops of a 2 per cent, solution of cocaine 

 are placed in the eye previous to operating. Deposit the bit of tissue 

 with fine sterilized forceps or a platinum loop through the opening 

 upon the iris, where it remains, and its pathogenic properties upon 

 the iris can be conveniently studied. The application of this mode 

 of inoculation is very limited. Cohnheim employed this method in 

 demonstrating the infectious nature of tuberculous tissues, tubercular 

 iritis being a constant symptom when tubercular matter was intro- 

 duced into the anterior chamber of the rabbit's eye. 



CXLIV. METHOD OF INOCULATING RABBITS FOR 

 THE DIAGNOSIS OF RABIES. 



1. Remove the brain of the suspected animal, with antiseptic pre- 

 cautions, as soon as possible after death. 



2. Place a small piece of the brain or spinal cord in a mortar, and 

 thoroughly grind with a few c.c. of sterile water or bouillon. 



3. The operator must disinfect the hands and sterilize all 

 instruments. 



4. Anaesthetize the rabbit with ether, clip the hair from the head 

 between the eye and ear, wash the skin, and disinfect with ordinary 

 sublimate solution ( 66, p. 44). 



5. A longitudinal incision is made through the skin and sub- 

 cutaneous tissue in the median line, while a crucial incision is made 

 through the periosteum on one side of the median line, thus avoiding 

 haemorrhage from the longitudinal sinus, and the four parts of the 

 periosteum reflected or pushed back. Cut out a piece of bone about 

 ^ of an inch in diameter with a trephine and expose the dura mater. 



6. Inject a drop or more of rabid material beneath the dura mater 

 with a hypodermic syringe, replace the periosteum, suture the skin, 

 disinfect, dry, and apply some iodoform collodion. Sometimes a piece 

 of the suspected tissue may be introduced directly under the dura 

 mater. The inoculation wound heals rapidly. Rabid symptoms may 

 appear in fifteen to thirty days, sometimes earlier than fifteen days, 

 and again from one to three months may intervene. 



CXLV. OBSERVATION OF ANIMALS AFTER 

 INOCULATION. 



Inoculated animals must be kept under constant observation, and 

 the following conditions noted : 



