CONCLUSION. 189 
monstrates that this expansive power is essentially 
derived from the Nervous System; the same 
thing is proved by applying nitrate of silver over 
the course of a nerve proceeding to a paralytic 
limb. The expansion of the iris and the corpora 
eavernosa penis have thus been reconciled with 
the expansion of the muscular fibres. Involun- 
tary contraction proceeds most commonly from the 
operation of the blood, and from all other causes 
which either directly or indirectly reduce the 
Vital Force; and if the expansive and contractile 
powers, which alternately operate on the fibres, be 
modifications of positive and negative Electricity, 
expansion and contraction are readily explained. 
The sensation of Clonic spasm resembles an 
Electric shock so closely, that it is impossible to 
distinguish the difference between the two sensa- 
tions. But whatever may be the nature of the 
Vital Force, its expansive power being at the 
command of the practitioner, may be turned to 
practical account. 
I have already stated the analogies between 
Galvanism and the Vital Force, which led to the 
experiments on the decomposition of aliment ; 
it is, therefore, unnecessary to recapitulate these 
resemblances in this place. Whether, therefore, 
the Vital Force be considered as a power gene- 
rating Caloric, or causing the compound motion 
of Irritability, or decomposing substances sub- 
