CHANGES IN THE RED CORPUSCLES BY ELECTRICITY. 389 



that it is better to provide the copper pole with clips than with 

 hooks. In these the ends of the induction coil or the ends of a 

 transversely divided discharging rod of a Leyden flask are re- 

 ceived, so that the tin-foil electrodes make a complete arc of union 

 with the blood found between them and the wires. In order to 

 enter more minutely into the phenomena which can be observed 

 under the microscope, it is necessary in the first instance to 

 bear in mind the results of microscopic experiments. 



If the blood of a mammal be introduced into the arc of discharge 

 of a Leyden phial, and a series of shocks be passed through it, it 

 becomes altered, losing its opacity, and assuming a transparent 

 lake-like tint. Microscopic examination shows that the blood 

 corpuscles become altered, ultimately presenting only extremely 

 delicate, pale, and feebly refracting particles. If in a consecutive 

 series of examinations the number of the discharges requisite to 

 produce the most complete transparency possible be taken as 

 a measure of comparison for the clarifying power of the dis- 

 charging current, we arrive at the following conclusions : 



The action of each successive shock is superadded to those 

 which precede it. 



The transparency of each element of the conductor formed 

 by the blood is dependent on the intensity (density) of the 

 current acting upon the unit of its transverse section with 

 which it proportionally increases ; it is also dependent upon 

 the amount of what may be termed the specific resistance of 

 the blood corpuscles, which differs in different kinds of blood, 

 and with the increase of which, though not in a hitherto clearly 

 ascertained ratio, the clarifying influence diminishes. 



With a given specific resistance of the blood corpuscles, and 

 with given size and specific conductivity of the blood, the course 

 of the phenomena can be varied according to the quantity and 

 mean intensity of the electricity in the phial. 



The most advantageous distance of the tin-foil electrodes 

 from one another for microscopic investigations is six mil- 

 limeters ; between these a thin layer of blood, covered with 

 a thin plate of glass, should be introduced, and a Leyden 

 flask employed, presenting a surface of about five hundred 

 square centimeters, with a striking distance of one millimeter. 

 Striking distances of greater extent cannot be used, as the 



THE ^ 



