408 OBSERVATIONS AND EXPERIMENTS 



There are many instances on record of the immunity of certain 

 animals from certain injurious agencies which are destructive of 

 most others. I have collected a larg-e number of such accounts, but it 

 would lead us too far from our object to mention them in detail, the 

 more so, that they are often very indefinite and not well authenti- 

 cated. Teleologically, the comparison with the immunity of vipers 

 from their own poison, proved by Fontana, is the nearest. Although 

 Fontana had shown that non-poisonous snakes, lizards, toads, eels, 

 snails and leeches are also proof against the viper's poison like the 

 viper itself, yet the immunity of the viper suggested the notion 

 and afforded support to it, that animals are fundamentally proof 

 against a poison produced by themselves. But this is not always 

 the case. Fontana had already remarked, that animals with corro- 

 sive and acid secretions, like the hymenoptera are not proof 

 against their own poison 1 . 



And this brings us to the point with which we are here con- 

 cerned. All those immunities relate to substances acting in a 

 specific manner, and which can therefore be resisted by a specific 

 organisation. That strychnine in such small amounts kills most 

 animals, is at bottom more remarkable than that the fowl 2 , the 

 rhinoceros bird and the sloth 3 can resist it more or less. But 

 immunity from a natural power like electricity, gives at first sight 

 almost the impression as if an animal were proof against a corrosive 

 or a metallic poison, against mechanical force or destructive heat. 



This is however a deceptive appearance. The electric current 

 stands to nerve and muscle in as peculiar a relation, as according to 

 modern ideas, certain organic molecules do to certain limited 

 provinces of the nervous system, and it is ultimately not more 

 wonderful, that in this special relation variations occur in the case 

 of certain animals, than that other animals are relatively proof 

 against the strychnine molecule which is so formidable to all 

 others. Along with the effects which the current produces in 

 animals, in virtue of its special relation to nerve and muscle, it is 

 capable of other, more general effects, which, if increased beyond a 

 certain degree, become likewise destructive to the animal in its 

 thermic, electrolytic, cataphoric and anaphoric actions. That 

 electrical fishes are not exempt from these actions is clear. This 

 consideration does not in the least detract from the importance of 



1 Abhandlung uber das Viperngift, u. s. w., Berlin, 1787, 4. p. 15 ff. p. 155. 

 3 Lehubo in the Archiv fUr Anatomie, u. s. w., 1867, P- 629. 

 8 Ibid. 1868, p. 756. 



