ACTIOX OF ELECTRIC SHOCKS ON BLOOD. 51 



nish two slips of gold-leaf or tin-foil, with pointed 

 ends which almost meet in the middle of the slide 

 (Fig. 14, A). A drop of blood is put here, the cover- 

 glass is placed over it, and the portion of blood which 

 lies between the points is brought under observation. 

 Or a moist chamber may be employed, the cover- 

 glass used having previously had two strips of tin- 

 foil cemented to^it (Fig. 14, B). The drop of blood, 

 being spread out in a thin layer between their 

 points, is quickly inverted over the ring of putty and 

 brought under observation. The tin-foil slips are 

 kept isolated from the brass-work of the microscope, 



Fig. 15. 



Apparatus for passing electric shocks through a drop of blood, which is 

 to be examined in a moist chamber. The tin-foil slips are cemented 

 near their points to the under surface of the cover-glass, and their 

 free ends are clamped to isolated metal supports, connected by wires 

 to an induction coil. The tin-foil slips are isolated from the brass 

 stage of the microscope by the glass slide on which they rest. 



and are so arranged that the charge of a small 

 Leyden jar, or an induced current of electricity, can 

 be passed through them at any moment (Fig. 15). 



