116 Some Observations on [Feb, 



fravitation. We are acquainted with the cause of lightning, 

 ecause Franklin proved it to be the same which produces the 

 other phenomena of electricity. Can we show that the pheno- 

 mena of any or all of the foregoing living powers depend on the 

 same cause which operates in the production of other phenomena? 



With regard to the sensorial power, it seems to require but a 

 moment's reflection to answer this question in the negative. 

 There is no real analogy between the effects of this power and 

 the phenomena observed in any other part of nature. Certain 

 fanciful analogies of this description have, indeed, from time to 

 time been suggested J but while they have pleased in the writ- 

 ings of the poet, by the philosopher they have been justly 

 rejected. To a careful observation and judicious arrangement of 

 the phenomena of the sensorial power, therefore, our study of it 

 must be confined. 



With regard to the nervous power the case is very different. 

 The principle which operates in many other instances may be 

 the means of exciting the muscles, of conveying impressions to 

 and from the sensorium, of effecting the formation of the secreted 

 fluids, and of causing an evolution of caloric from the blood. The 

 most subtle of known agents, electricity, naturally suggested 

 itself as the cause of the phenomena of the nervous power ; and 

 when Voltaic electricity, and its signal influence on the muscular 

 system, were discovered, a material step it was imagined had 

 been made towards ascertaining the nature of this power. On 

 more mature reflection, however, it was admitted, that to ascer- 

 tain that any power is capable of exciting the muscular fibre, is 

 to go but a very short way towards establishing its identity with 

 the nervous influence, a very large proportion of bodies possess- 

 ing this property ; and of late the opinion appears to have been 

 abandoned ; nor can it be maintained on any other grounds than 

 by showing that Voltaic electricity is capable of the more charac- 

 teristic as well as the more simple functions of the nervous 

 influence. 



This I have attempted to do in the above-mentioned treatise. 

 It appears from Experiments 46, 47, 48, 49, that Voltaic elec- 

 tricity is capable ©{'effecting the formation of the secreted fluids 

 when applied to the blood in the same way in which the nervous 

 influence is applied to it ; and from Experiments 64, 65, 66, 67, 

 that it is capable of occasioning an evolution of caloric from 

 arterial blood. When the lungs are deprived of the nervous 

 influence, by which their function is impeded and soon destroyed ;. 

 when digestion is interrupted by withdrawing this influence from 

 the stomach ; can we suppose that any thing will renew the 

 functions of these organs but restoring to them the influence of 

 which they have been deprived? Their functions are renewed by 

 exposing them to the influence of a Voltaic trough. Many col- 

 lateral observations appear to support the inference, which, 

 from these facts alone, seems to be unavoidable. See p. 139 



