242 CLINICAL DIAGNOSTICS. 



If rabies is present the first symptoms appear in from 2 

 weeks to 23 days ; the animals are shy, crawl away, and show 

 loss of appetite. After 12 hours paralysis and difficult deglu- 

 tition is observed, the animals emaciate rapidly, grit their teeth 

 and emit a cry when touched on the head. The disease, thus 

 produced, terminates fatally within 48 hours. 



2. Subdural Inoculation. Carefully trephine the 

 frontal bone of a rabbit, observing the necessary antiseptic 

 and anatomical precautions. By means of a sterilized glass 

 syringe having its nozzle bent at right angles, inject a few 

 drops of the emulsion under the duramater, stitch the wound 

 and protect with collodion, or absorbent cotton. 



If the inoculation material is fresh and virulent, death 

 will follow in two or three weeks. Sometimes the animals 

 die as early as the 11th day, or may live until the 30th day. 

 [In some cases six weeks will elapse before the first symptoms 

 of the disease can be observed.] 



3. Intra-muscular Inoculation. If the suspected nerve 

 tissue has begun to decompose, or if suspicion exists that it 

 may not be fresh, it should be immersed in a one-half per cent, 

 solution of carbolic acid and placed in the refrigerator for 24 

 hours. It is then removed and carefully triturated with 

 beef broth until a fine emulsion results. Rabbits receive from 

 three to five cubic centimeters of this emulsion injected into 

 the dorsal muscles in the region of the loins. As a rule septic 

 infection can be avoided in this way while the virulence of 

 the material is otherwise unaffected. Death follows after two 

 or three weeks or somewhat later. 



The symptoms following subdural and intra-muscular in- 

 oculation are much the same. After ten or twelve days ema- 

 ciation sets in, followed by paralysis of the hind parts, and 

 death two or three days later. 



4. Subconjunctival Inoculation. This is recoup 

 mended by Szpilman as easy of execution and certain in its 

 results. 



