152 RKICHRL : 



shown that rabies did exist in a dead animal was 1)y experi- 

 mental inoculation. Rabbits inoculated with material of an 

 animal suspected of rabies were kept under observation. If 

 rabies existed the rabbit would develop the disease on an 

 average of 22.5 days — some as short as nine days; longest 

 period observed, 78 days. A person bitten was obliged to 

 wait from 9 to 78 days to learn whether or not he or she was 

 exposed to the disease. 



Babe, as early as 1892, reports observation made micro- 

 scopically of sections of the spinal cord and medulla oblougala 

 ot cases of rabies in man and dogs. From his investigations 

 he insisted that an increase or proliferation of the endothelial 

 cells, which form the Ijnnph sacks surrounding the nerve cells, 

 with degeneration and destruction of the nerve cells, are spe- 

 cific pathological changes of rabies. 



Van Gehucten and Nelis, after careful examination of the 

 various parts of the nervous system of a man dead of rabies, 

 found that in the nerve ganglion, particularly in the intraver- 

 tebral ganglion, a marked proliferation of the endothelial 

 cells, with nerve degeneration and destruction. 



The examination then of those tissues wherein those 

 changes described by Babe and \"an Gehucten and Nelis took 

 place, made it possible to determine the absence or presence of 

 these changes, upon which a diagnosis could be made. Where 

 the changes are present, a positive diagnosis can be made in 

 from 36 to 48 hours, but if the changes are absent no diag- 

 nosis is made. The animal inoculation test is then relied 

 upon. The changes are found in 95 per cent, of the positive 

 cases, but that they are only seen in the cases of rabies has 

 been disproven . 



Ravenel and McCarthy found that the identical changes 

 occurred in cattle afflicted with forage poisoning. They are 

 also said to occur in animals dead of tetanus. Other investi- 

 gators have found that the changes are sometimes seen, 

 although rabies was not present. At our own laboratory, 

 during the year 1906, well marked proliferation changes were 



