CHAPTER VIII. 



TESTING IN VACUO 



I DEVISED an apparatus some years ago, and made 

 brief mention of it in Electro-Pathology, for the purpose 

 of putting to the test certain theories I held of the origin 

 of currents exhibited by animal and vegetable skins, mucous 

 membranes and excised matter generally. Owing, however, 

 to causes into which I need not enter the apparatus was 

 not constructed until the year 1916. The following is a 

 photograph of it : 



Fig. 79— Apparatus for Testing in Vacuo. 



The air-pump was a double-acting one. The table shown 

 above the bedplate consisted of a disc of cork, 4J-inches 

 in diameter, dried in an oven, boiled in paraffin wax, and 

 affixed by means of Chatterton's compound upon cork 

 supports which had been similarly treated, to the bedplate. 

 Holes 1/lOth-inch in diameter were drilled in the latter, to 

 admit flexible wires, and made air-tight by the compound ; 

 to each of the wires where they terminated at the table a 

 steel needle was carefully soldered. 



