DIAGNOSTIC INOCULATION. '241 



hzed (flamed) knife, apply some of the suspected material to 

 the surface of one half, replace the other half, pack carefully 

 and send it to the official bacteriologist. Blood sent in a flask, 

 is usually not adapted for microscopical examination. 



IV. Rabies. 



Suspected dogs are usually killed before they can be sub- 

 jected to examination by an expert. A post mortem examina- 

 tion will then hardly enable us to make a definite positive 

 diagnosis ; we must resort to inoculation of a test animal. 

 The diagnostic inoculation of a rabbit 

 with the brain matter ofa suspecteddog 

 is the only absolutely safe method of 

 definitely determining the presence of 

 rabies. 



Technique. The brain and cervical cord of the sus- 

 pected dog are carefully removed. The medulla oblongata is 

 severed from the brain by an incision, at the pons Varolii, 

 made with a "flamed" knife. A piece of the medulla (size of 

 a pea) is removed with sterilized scissors from the cut surface, 

 placed into a sterilized porcelain vessel and thoroughly tritu- 

 rated with a small quantity of distilled water. This emulsion 

 is used for inoculation. 



1. The Intra-ocular method according to Johne. Two 

 rabbits are inoculated, each receiving a few drops of the emul- 

 sion into the anterior chamber of the eye; injected with a ster- 

 ilized hypodermic syringe. If the hypodermic needle is fine 

 and sharp and the rabbit's eye has been previously dis- 

 infected and anesthetized the operation can be per- 

 formed with little difficulty. We insert the needle at the bor- 

 der of the cornea, directing it toward the median line. If the 

 operation was carefully conducted a slight turbidity of the 

 cornea, which soon disappears, is the only symptom that fol- 

 lows. 



