1890.] MICROSCOPICAL JOURNAL. 171 



tion produced by the passage of an electric current through living mus- 

 cle, thus presenting an even greater state of fluidity to tbis tissue under 

 such conditions. It must be remembered also that all tissue is sustained 

 to a greater or less extent by a circulatory system, and that even among 

 the more solid portions of the organism, bone has as much as 23 per 

 cent, of water entering into its composition combined with the salts of 

 the blood circulating in the canaliculi traversing it. The influence 

 of adipose tissue and the epidermis, factors mentioned (Kemmier en- 

 quiry) as presenting a marked resistance to the passage of the electric 

 current, must be considered in this connection. 



The fat of the body is intermingled with the various tissues of the 

 body, is also nourished b}' a vascular blood supply, and in very few in- 

 stances (except possibly abnormal states) does it present an unbroken 

 barrier to the electric force. In the epidermis, where the greatest re- 

 sistance is oflered, the vascularity produced by the sudoriparous 

 (sweat) ducts, without taking into consideration the capillaries of the 

 papillary derma, would, it seems, be sufficient to eliminate any uncer- 

 tainty. Furthermore, it is well to note that the animal organism pre- 

 sents a somewhat compact mass with the exception of the intestinal 

 canal and thoracic cavity in expiration ; that outside of this there is prac- 

 tically no break of continuity t6 the passage of an electric current. 



i^'rom these generalizations and the statement that fluids with the 

 potassium and sodium salts are better conductors than pure water, it is 

 reasonable to assume that the animal organism, through its great vascu- 

 larity and chemical composition, presents a medium that may be looked 

 upon as a fairly good conductor of electricity ; its real value as a con- 

 ductor will be considered later. 



It may be noted that investigation of these subjects cannot well be 

 carried on without utilizing the microscope. The unfamiliarity of many 

 with the nomenclature employed in the discussion of subjects pertain- 

 ing to electricity, requires a short explanation regarding the terms most 

 frequently used. We assume that all are familiar with the methods of 

 electro-decomposition, illustrated practically in electro-plating. The 

 compound fluid termed an electrolyte being traversed by the electric 

 current of sufHcient strength to overcome the chemical aflinity existing 

 between its molecules, is broken up into a more elementary state and 

 the metals, the salts of which were present in the fluid, are de})osited 

 at the electrodes. This eflect is termed electrolysis ; that electrode 

 connected with the positive pole is the anode ; that with the negative 

 pole, the cathode ; electro-positive elements appear at tiie negative, and 

 the electro-negative elements at the positive electrode. 



Electro-motive force is the power produced by the electrical genera- 

 tor, be it a galvanic cell, a voltaic pile, or a dynamo. The electro-motive 

 foi-ce of a Daniell standanl cell is one volt, the electro-motor unit of 

 measurement. In a standard Daniell cell there is a uniform internal 

 resistance to the transmission of the electro-motive force which is 

 termed an ohm, and is the unit of resistance to the passage of the cur- 

 rent. 



The electrical current passing through a standard Daniell cell has an 



electro- motive force of one volt and is termed an ampere. Ohm's law 



E 

 is represented by the equation C=-g ,or the strength of the current is equal 



