I must anticipate a number of objections that, if they had foundation, would diminish and even cancel the worth of my experiments. I do not raise these objections for the pleasure of refuting them but advance them in all seriousness.

The sensitiveness of the face is such that one is not able to spare the subject submitting to this type of experiment a disagreeable sensation and even a little pain. Now this sensation can cause involuntary movements. How do we distinguish these latter movements from those that are actually appropriate to the muscle excited?

In general, these involuntary movements are only seen upon the first application of the electrodes, and not in those individuals who are used to the electrical sensation. Besides, we will see later, in order to dissipate doubts that could be raised by this objection, I chose as the principal subject for my experiments a man whose facial sensibility was poorly developed. Finally, these same experiments were repeated on a fresh cadaver and gave absolutely identical results.

Could not the isolated contraction of a muscle that presides over a particular emotion enable it to react on the soul, and produce an internal feeling that would provoke other involuntary contractions in sympathy? Two facial muscles might contract, for example, one of which draws the fundamental lines of an emotion, while the other completes the expression (I will demonstrate this at an opportune time).