AMMAN, JOHANN CONRAD, a physician, and one of the earliest writers on the instruction of the deaf and dumb, was born at Schaffhausen, in Switzerland, in 1669. In 1687 he graduated at Basle; and as his religious principles did not permit him to settle in his native country, he retired to Holland, where he appears to have devoted his time and attention chiefly to the cure of the defects and imperfections of speech. He first called the attention of the public to his method, in a paper which was inserted in the Philosophical Transactions; and which appeared in a separate form in the year 1692, under the title, Surdus Loquens, sive Methodus quæ qui surdus natus est loqui possit; and afterwards, with much additional matter, in 1702 and 1728, under the title, Dissertatio de Loquela, quæ non solum vox humana et loquendi artificium ex originibus suis eruntur, sed et traduntur media, quibus ii qui ab incunabulis surdi et muti fuerunt, loquelam adipisci, quique difficulter loquantur, vitia sua emendare possint. In this work, which Haller terms "vero aureum," he develops, with great ability, the mechanism of vocal utterance, and describes the process which he employed in teaching its use to the unfortunate class of persons committed to his care. This consisted principally in exciting the attention of his pupils to the motions of his lips and larynx while he spoke, and then inducing them by gentle means to imitate these movements, till he brought them to repeat distinctly letters, syllables, and words. As his method was excellent, we may readily give him credit for the success to which he lays claim. In a long course of practice, he says that he never failed in his endeavours but in two instances; one of which was that of a girl who was an idiot, and the other that of a Jew, from whose father he foresaw that he would not get any thanks for his trouble. The edition of Cælius Aurelianus, which was undertaken by the Wetsteins in 1709, and still ranks as one of the best editions of that author, was superintended by Amman. (τ. 3.)