IN DENTAL OPEEATIONS. 91 



sex, constitution, condition of the teeth, gums, 

 &c., and the amount of power employed, and 

 effect produced, discriminating, however, care- 

 fully between effects attributable to the operation 

 itself or to the sensations derived from the electric 

 shocks. 



As an electrician of more than thirty years' 

 experience, I have not failed to discover that it 

 is not yet possible either to prognose or diagnose 

 with certainty. Abnormal conditions, apparently 

 identical in external symptoms, originate in very 

 different causes, and the treatment which is per- 

 fectly successful in one case not unfrequently 

 turns out quite the reverse in another, apparently 

 similar in all respects. Up to a certain point, 

 then, experience derived from patient investigation 

 will be found to be the safest guide^ 



