NATURAL PHILOSOPHY. 131 



sions, brought to a white electric heat, he undertakes many operations com- 

 monly performed with cutting instruments. The heating agent is a Grove's 

 battery; and, properly employed in an operation, there is no hemorrhage of 

 the small vessels; the action is energetic and limited, can be sustained or 

 cut off at pleasure, and applied through narrow passages, and to depths 

 never attempted in ordinary cauterization. Mr. Middeldorp says: "This 

 intelligent fire let me be pardoned the expression admits of cutting, 

 splitting, of cutting away, of cauterization on a single point or in rays, or 

 over large surfaces, of stopping hemorrhage, of provoking inflammation of 

 certain tissues, of coagulation of the blood, of suppuration, and the develop- 

 ment of proper granulations. In short, beinc: introduced cold, the galvano- 

 caustic instruments inspire no fear in the patient, but once in place, a touch 

 of the finger suffices to raise them to a glowing heat," and the wished-for 

 effect is speedily produced. Of four hundred operations performed by Mr. 

 Middledorp with the "intelligent fire," not one has been followed by ill 

 results. 



THEPtAPEUTIC USES OF ELECTRICITY. 



From an article in the British and Foreign Medico- Chirurgical Review, "On 

 the Therapeutic uses of Electricity," we derive the following extracts, which 

 are illustrative of the mechanical philosophy of this agent, and its physiologi- 

 cal effects when applied to vital animal tissue. In speaking of electric currents, 

 the writer says : 



"The degree of tension, or intensity of the electric current is, however, 

 more influential than its quantity in determining physiological results; and 

 it is to variations in this quality that we ordinarily apply the terms ' strong' 

 and ' weak.' There are several currents in common use for physiological 

 experiment and therapeutical exhibition; and as this quality of tension or 

 intensity is predicated of all of them, it is necessary that we should describe 

 separately the conditions upon which its variations depend. But before doing 

 so, inasmuch as some confusion has crept into the language of modern elec- 

 tricians, we will state as concisely as possible what these several currents arc, 

 what are their proper names, and in what way they have been erroneously 

 designated. 



" In the wire which unites the two poles of a voltaic arrangement 

 whether this consists of one pair of plates, or of one hundred pairs there 

 is, when the wire is unbroken, a current of electricity, termed the 'initial 

 current.' This passes in the direction from the copper or negative metal, 

 through the wire to the zinc or positive plate. If this Avire is broken, and the 

 two ends of it are grasped by the hands, the individual so doing becomes, in 

 that part of his body Avhich intervenes betAveen those tAvo ends, a part of the 

 A'oltaic apparatus; and the initial current passes through him in the direction 

 described. If this Avire, if any part of its course be broken, there is at the 

 moment of division, and existing at that moment only, another current set- 

 ting in the opposite direction to that taken by the initial current. This has 

 receiA'ed various names : Duchenne has termed it an ' induced current of the 

 first order/ but its proper designation is the 'extra current.' 



"Another Avire placed near and parallel to the conducting wire viz., that 

 through Avhich the initial current passes has its polar condition so affected 

 that an ' induced current ' is propagated through it in an opposite direction to 

 the initial current. Several of such \vires may be employed, at different de- 

 grees of proximity to the conducting wire, and in all of them there is an in- 



