HYDROPHOBIA. 395 



liquid of serpents, scorpions, wasps, and bees. In respect to 

 all these one remark is applicable, viz. that neither chemical, 

 nor microscopical, nor any other scrutiny has been hitherto 

 made to reveal any agent, material, or quality, with which 

 the result can be rationally associated. 



Passing in quick review such members of the long series 

 of animal poisons as now occur to the mind, I can only think 

 of one that chemistry is able to reveal ; namely, cantharidine, 

 or the blistering principle of Spanish fly ; and even in respect 

 of this, chemistry is so far at fault, that analysis merely 

 reveals the poison without individualising it. Ultimate evi- 

 dence of the presence of cantharidine is physiological. If 

 dropped upon the skin, it raises a blister, in which the result, 

 blistering, is the proof. As already remarked, very little 

 doubt exists but that the only way of conveying hydrophobic 

 poison to the human subject is by inoculation ; and, the con- 

 tingencies of accident regarded, the only inoculative fluid is 

 saliva : nevertheless, the fact has been established by Huf e- 

 land and others, that the blood of a hydrophobic animal is 

 quite competent to propagate the disease by artificial inocu- 

 lation. All species of warm-blooded animals upon which 

 hydrophobic inoculation has been performed have demon- 

 strated, by the result, susceptibility to the disease, but not 

 all individuals of each species. 



That is to say, the hydrophobic poison, whether com- 

 municated by bite, lick, or artificial puncture, is very un- 

 certain in its action. If an animal be bitten by an adder, 

 if it be stung by a scorpion, wasp, or bee, the antecedent of 

 puncture or poison-injection will be infallibly followed by 

 consequent symptoms of poisoning. Not thus in respect to 

 hydrophobia ; for whilst some inoculations take effect, others 

 do not, and these the majority. Dr. Hertwich, professor at 

 the veterinary school at Berlin, inoculated fifty dogs with 

 hydrophobic poison, but of these only fourteen were affected. 

 Similarly to the poison of serpents, moreover, that of hydro- 



