Rabies and Hydrophobia. 307 



apart from putrefaction. Such laboratory results must however 

 be qualified by the facts recorded by Blaine, Youatt and others in 

 which hound after hound died of rabies from living in a dry 

 kennel in which a rabid animal had preceded them. Until we 

 know the living germ itself of rabies, it is unwise to in- 

 fer too positive results from experiments on that microbe, in 

 what may be but one stage of its existence. 



The virus is very resistant to cold, having survived a tempera- 

 ture of— 6o°C. (—76° F.) for several hours (Roux), —10° C. 

 ( — 14° F.) for ten months (Jobert). Virulence is destroyed 

 however by a temperature of 48° C. (118. 4°F.) in five to twenty 

 minutes (Galtier). I/ight destroys the virulence in 14 hours at 

 30° to 35° C. (Celli), but encreased pressure has little effect on it 

 (16 atmospheres, Nocard and Roux). 



Glycerine at room temperature preserves the medulla in its full 

 potency for four weeks, but destruction ensues if it is heated 

 (Protopopoff). An aqueous solution of iodine (6:100) destroys 

 the virulence (Galtier), as does also citric acid, bromine, chlorine, 

 sulphurous acid, the mineral acids and cupric sulphate. 



Ratio of successful inoculation to bites of rabid animals. As 

 rabies is usually transmitted by the bite, it is well to note that 

 not all the bites of rabid animals are effective. Of 183 dogs 

 confined with and bitten by a rabid dog 91 contracted rabies ; of 

 73 cattle bitten 45 became rabid ; out of 121 sheep bitten 51 suc- 

 cumbed and of 890 persons bitten, 428 took hydrophobia. Of 

 440 persons bitten by rabid wolves 291 contracted the disease. 

 ■The escape of such a large proportion is variously accounted for. 

 Wolves naturally attack the face, throat or hands where there is 

 no protection by clothing, and inoculation is therefore much more 

 certain. Dogs, especially in cold weather usually bite man 

 through the clothes which wipe off the virus from the smooth 

 conical teeth before they reach the skin. lyong haired animals 

 are often protected in the same way. In other cases the bite is 

 sustained on a very vascular part and the ^ free flow of blood 

 washes out the poison. In still other cases the rabid animal 

 making a number of snaps in rapid succession comes to the last 

 with the teeth wiped clean and harmless. Again the prompt 

 washing or cauterizing of the wound tends often to protect 

 against infection. 



