PHYSIOLOGICA L PH \ 



[Chap. XV. 



Fig. 78. Stohrer's Battery. 



For the constant current, types of batteries may 

 be taken in the STOHRER and the LECLA.NCHE. 



Stohrer's battery is figured in Fig. 78. It consists 

 of a case containing twenty to thirty cells of vulcanite 



containing a 

 plate of carbon 

 and a plate of 

 zinc, the cell 

 being half full 

 of dilute sul- 

 phuric acid with 

 a little bisul- 

 phate of mercury 

 for keeping the 

 zincs amalga- 

 mated. In one form a small quantity of strong 

 solution of chromic acid is added, and gives the fluid a 

 claret colour. 



The plates are fixed at the upper part of the box 

 on a wooden support. The cells can be raised by a 

 handle projecting at each end, so that they can be 

 raised up to meet the plates, which are so caused to dip 

 into the solution, and the cells can also be lowered so 

 that the plates are out of the solution. When the 

 cells are raised they can be fixed by a half turn of the 

 handle. The plate carrier carries a sledge, which on 

 its under surface makes contact by means of two 

 metal rails with the plates. The plate carrier has 

 numbers marked on it which indicate the number of 

 cells in circuit when the sledge is over that place. 

 The sledge should be so placed as to cover three wires 

 of the cells, the central wire of which tells the number 

 in circuit. The metal rails are long enough to make 



o O 



contact with the next cell before they break contact 

 with the one before. So that if a current is being 

 passed through a patient's body it is not necessary to 

 break the circuit in order to throw in more cells, but 



