MECHANICAL APPLIANCES, ETC. 221 upon the larynx can be increased or diminished, as may be required. " From the above description it will be seen that the efficiency of these instruments is entirely dependent upon the unob- structed channel which they preserve for the egress of the vi- brating column of breath from the larynx, through the mouth into the open air. Muscular spasm is necessarily removed, and the self-confidence of the stammerer restored — undoubt- edly the great desideratum in this affection. When the patient is fully convinced that he can really enunciate the opposing letters as distinctly as his friends, he rapidly overcomes the disease, by the judicious and effective exertions which renewed confidence begets. " An advantage of some importance possessed by this appara- tus is, that it can be worn without attracting notice, two of the pieces — the tube for the palatal and the belt for the guttural sounds — being entirely concealed; while the tube which projects externally from the silver disk may be disguised by slipping over it the barrel of a quill, cut like a tooth-pick. Moreover, each of the pieces can be most easily and expedi- tiously applied, as occasion may require. . . . "By order of the Committee, "WILLIAM HAMILTON, Actuary." 1 This collection of machinery was sent to the stam- merer on payment of fifteen dollars. If he retained it in his possession for a longer period than four months, he -was required to pay another fifteen dollars; but he then became the lawful owner of the equipment. Instruments similar to "Bates' Appliances" may still at times be encountered. 1 Quoted from The Voice, Vol. VI, p. 141.