y the 1800s, electrical sciences and the medical applications of electricity had progressed to the point where electrical shocks were known to produce powerful muscle actions in freshly killed as well as living tissue. Consequently, devices that could store electric charges produced by an electrostatic generator were needed. The Leyden jar was invented to serve this purpose. It could store a large charge that could then be released all at once, creating a very strong electrical shock. 

Medical science of the late 1700s and early 1800s saw the human body as mechanical; like any machine, it should respond predictably to stimuli.  Electricity was considered the most potent means of stimulating reactions within the body.  It was soon found that connecting Leyden jars in parallel increased electric current during a discharge, resulting in strong electrical discharges and unprecedented reactions in a body.  The bodys reactions to a battery of Leyden jars were so extreme, scientists thought the shocks could revive the apparently dead.