Less of practical value can be learned of sign language, considered as a system, from the study of gestures of actors and orators than would appear without reflection.  The pantomimist who uses no words whatever is obliged to avail himself of every natural or imagined connection between thought and gesture, and, depending wholly on the latter, makes himself intelligible.  On the stage and the rostrum words are the main reliance, and gestures generally serve for rhythmic movement and to display personal grace.  At the most they give the appropriate representation of the general idea expressed by the words, but do not attempt to indicate the idea itself.  An instance is recorded of the addition of significance to gesture when it is employed by the gesturer, himself silent, to accompany words used by another.  Livius Andronicus, being hoarse, obtained permission to have his part sung by another actor while he continued to make the gestures, and he did so with much greater effect than before, as Livy, the historian, explains, because he was not impeded by the exertion of the voice; but the correct explanation probably is, because his attention was directed to ideas, not mere words.

GESTURES OF ACTORS.

To look at the performance of a play through thick glass or with closed ears has much the same absurd effect that is produced by also stopping the ears while at a ball and watching the apparently objectless capering of the dancers, without the aid of musical accompaniment.  Diderot, in his Lettre sur les sourds muets, gives his experience as follows: 

“I used frequently to attend the theater and I knew by heart most of our good plays.  Whenever I wished to criticise the movements and gestures of the actors I went to the third tier of boxes, for the further I was from them the better I was situated for this purpose.  As soon as the curtain rose, and the moment came when the other spectators disposed themselves to listen, I put my fingers into my ears, not without causing some surprise among those who surrounded me, who, not understanding, almost regarded me as a crazy man who had come to the play only not to hear it.  I was very little embarrassed by their comments, however, and obstinately kept my ears closed as long as the action and gestures of the players seemed to me to accord with the discourse which I recollected.  I listened only when I failed to see the appropriateness of the gestures..  There are few actors capable of sustaining such a test, and the details into which I could enter would be mortifying to most of them.”