[ I 
negative. But where does the pofitive 
electricity refide'? and where the negative ? 
Profeffor Galvani, in order to eftablifh this 
point, brought cylinders of glafs and feal- 
ing-wax near the fpinal marrow of frogs; 
the former did not produce any move¬ 
ments, but they were excited by the latter. 
If the back of the animal was covered by 
a plate of metal, tin for inftance, although 
it might be at the difiance of four lines or 
more, yet the fealing-wax excited rmifcu- 
lar motion. Having brought the animal 
near the plate of the machine, after having 
turned it feveral times, no motion was 
produced* 
The author then made every poflible 
attempt in the fame manner to excite mo¬ 
tion in the mufcles, but without fuccefs. 
From hence Galvani concludes, that the 
pofitive electricity refides in the nerves or 
the inner furface of the mufcles, and the 
negative in the outer furface, or both 
equally 
