OF MOISTURE AS A CONDITION OF VITAL ACTIVITY. 97 



employed remedially in many states of disordered nutrition ; in virtue 

 of its power of modifying the operations of the Vital forces. 



147. The closest relations of Electricity, however, are with the proper 

 Animal functions; for these, as will be shown hereafter, are more 

 directly and obviously subject to its influence, than are the Organic. 

 Thus Electricity, when transmitted along a Nerve, whether sensory ox 

 motor, a nerve -of "special" or one of "common" sensation, is capable 

 of calling forth all the actions of which that nerve is the instrument ; 

 and, when brought to bear on a Muscle, it immediately excites a con- 

 tractile movement. It is probably through the influence of this agent 

 upon the Nervous system, that electric states of the atmosphere induce 

 in certain individuals a degree of languor and depression, which cannot 

 be accounted for in any other way. An instance is on record, in which 

 the atmosphere was ;n such an extraordinary state of electric disturbance, 

 that all pointed bodies within its influence exhibited a distinct luminosity ; 

 and it was, noticed, that all the persons who were exposed to the agency 

 of this highly electrified air, experienced spasms in the limbs and an ex- 

 treme state of lassitude. 



148. Animals, like Plants, are liable to be killed by shocks of Elec- 

 tricity ; even when these are not sufficiently powerful to occasion any 

 obvious physical change in their structure. But, as formerly mentioned 

 ( 69), there can be no doubt that minute changes may be produced in 

 their delicate parts, which are quite sufficient to account for the destruc- 

 tion of their vitality, even though these can only be discerned with the 

 microscope. The production of changes in the Chemical arrangement 

 of their elements, is, however, a much more palpable cause of death ; 

 since it may be fully anticipated beforehand, and can easily be rendered 

 evident. To take one instance only ; it is well known, that albumen 

 is made to coagulate, i. e., is changed from its soluble to its insoluble 

 form, under the influence of an electric current ; and it cannot be doubted 

 that the production of this change in the fluids of the living body (almost 

 every one of which contains albumen), even to a very limited extent, is 

 quite a sufficient cause of death, even in animals that are otherwise 

 most tenacious of life. " I once discharged a battery of considerable 

 size," says Dr. Hodgkin, "through a common Earth-worm, which would 

 in all probability have shown signs of life long after minute division. 

 Its death was as sudden as the shock ; and the semi-transparent sub- 

 stance of the animal was changed like Albumen which has been exposed 

 to heat." i 



4. Of Moisture, as a Condition of Vital Activity. 



149. Independently of the utility of Water as an article of food, and 

 of the part it performs in the Chemical operations of the living body, 

 by supplying two of their most important materials (oxygen and hydro- 

 gen), there can be no doubt that a certain supply of moisture is requi- 

 site, as one of the conditions without which no vital action can go on. 

 It has been already remarked, indeed, that one of the distinguishing 

 peculiarities of Organized structures, is the presence in all of them of 

 solid and liquid component parts ; and this in the minutest portions of 



