It is highly probable that actual contractions of the laryngeal muscles take place, under certain conditions, as an accompaniment to the listening to voices. This is evident in the case of extremely aggravated throaty and forced voices. In listening to the harsh, raucous cries of many street vendors, when calling out their wares, the hearer frequently feels a sense of actual pain in his own throat. Involuntary and unconscious contractions of the laryngeal muscles, somewhat similar to those under consideration, are well known to experimental psychologists. Prof. Ladd's statement that these contractions assist the ear in the judgment of absolute pitch has already been cited. Another example of unconscious laryngeal movements has been investigated by Hansen and Lehmann ("Ueber unwillkuerliches Fluestern," _Philos. Studien_, 1895, Vol. XI, p. 47), and by H. S. Curtis ("Automatic Movements of the Larynx," _Amer. Jour. Psych._, 1900, Vol. XI, p. 237). The laboratory experiments of these investigators show that when words, or ideas definitely expressed in words, are strongly thought but not uttered, the vocal organs unconsciously adjust themselves to the positions necessary for uttering the words. Curtis says of these unconscious laryngeal contractions: "Such movements are very common with normal people, and are comparatively easy of demonstration." The apparatus used by Hansen and Lehmann in their experiments consists of two large concave reflectors. These are placed at a convenient distance, one facing the other, so that two experimenters may be seated, the first having his mouth at the focal point of one reflector, the second with his ear at the focal point of the other. As the first experimenter repeats mentally any words or phrases, these are found to be unconsciously whispered. These sounds of whispering, inaudible under ordinary conditions, are so magnified by the two reflectors as to be distinctly heard by the second experimenter. Curtis proved that actual movements of the larynx unconsciously accompany intense thought. His demonstrations were conducted along lines familiar to all students of experimental psychology. Similar experiments would probably show that unconscious movements of the larynx also occur during the listening to vocal tones. A peculiarity of the laryngeal adjustments accompanying the listening to voices is seen in the fact that the possession of a fine or well-trained voice is not required in this process. It does not matter whether the physical organs are capable of producing fine musical tones. The nervous equipment alone is involved; this is frequently highly developed, even though the physical voice is very poor. A keen and highly-trained ear is the only requisite. Players in the opera orchestras often develop this faculty to a high degree, even though they may never attempt to sing a note. _Muscular Sense_