48 



Mr. G. F. Dowdeswell. 



rate of variation with the temperature of its thermal conductivity is 

 very probably much above the average. 



To reduce the results of the present paper to the C.G.S. system of 

 units, it is only necessary to divide them by 60. 



"On Rabies." By G. F. Dowdeswell, M.A., F.L.S., F.C.S. 

 Communicated by Professor Victor Horsley, F.R.S. Re- 



ceived May 9, — Read June 16, 1887. * 



[Plate Lj 



contents. Pag( 



I. Introduction 48 



II. Methods of preparation and inoculation with virus 49 



III. Symptoms and post-mortem appearances 50 



IY. Seat of virus and results of inoculation 58 



Y. Occurrence of infectivity in tissues 64 



VI. Duration of incubation period 66 



VII. Preservation and modification of virus 68 



VIII. Protective inoculation 70 



IX. Action of drugs 75 



X. Nature of virus 83 



XI. Conclusions 85 



Numerous as are the communications upon the subject of rabies, 

 the paucity of experimental investigation is remarkable ; the disease 

 has remained for upwards of 2000 years, since the first recorded 

 mention of it by Aristotle, exceedingly obscure in many essential 

 points. The unparalleled and variable length of its incubation period 

 has offered the greatest obstacle to systematic examination ; in the 

 words of John Hunter in the last century, " It has defied alike 

 scientific investigation as to its intimate nature, and all remedial 

 measures for its successful treatment." 



Lately, however, the results announced to have been attained by 

 M. Pasteur, have promised to remove these obstacles, and encouraged 

 research by new methods and with fresh views. 



This investigation was commenced early in 1885, during the preva- 

 lence of rabies in and around London. Two well-marked cases in 

 dogs were obtained, and inoculations with their saliva, taken both 

 during life and shortly after death, were made into the subcutaneous 

 tissue of other animals, but failed to produce infection. 



At that time I was not sufficiently conversant with the results of 

 M. Pasteur's investigations to place reliance upon his methods of 

 intracranial inoculation with the cerebro- spinal substance of a rabid 

 animal, and I musi admit that his statements seemed to me to be im- 



