Mad. E. Seiler has made for herself an honorable name in Germany, not only as a practical teacher of singing, but also by her valuable investigations in regard to the culture of the musical voice. By her own anatomical studies she has acquired a thorough knowledge of the vocal organs, and by means of the laryngoscope has advanced, in the way first trodden by Garcia, to the establishment of the conditions of the formation of the voice. We owe to her a more exact knowledge of the position of the larynx, and of its parts in the production of the several registers of the human voice; and she appears especially to have brought to a final and satisfactory decision the much-vexed question respecting the formation of the so-called _fistel tones_ (head tones). She has been associated with the best powers possessed by Germany in the department of the theory of music and physiological acoustics, standing by the side of the celebrated physiologist, Helmholtz, while he was engaged in his physiologico-acoustic work upon the generation of the vowels and the nature of harmony. (Signed) E. du Bois-Reymond, Professor of Physiology in the Royal University of Berlin. Berlin, July 17, 1866 In a letter, written in English, addressed to the President and Members of the American Philosophical Society, Professor du Bois-Reymond introduces Mrs. Seiler (italicizing the words) “_as a lady of truly remarkable scientific attainments_.” “Prompted,” he states, “by a spirit of philosophical inquiry, not frequently met with in her sex, she has made herself entirely acquainted with all the facts and theories concerning the production of the human voice. She has entered, deeper probably than any one else before her, into the study of the problem of the different registers of the human voice. Most of her results she has published in a pamphlet under the title: Altes und Neues über die Ausbildung des Gesangorganes (Leipzig, 1861), which has received the approbation of both the physiologists and the singing masters of this country.” * * * * * The translator takes the opportunity to state that, as he makes no pretensions to any knowledge either of the science or of the art of music, his translation has been carefully revised by persons entirely competent to correct its musical phraseology. W. H. F. Philadelphia, December, 1867. INTRODUCTION In giving to the public these fruits of years of earnest labor, and in attempting to bring into harmony things which have always been treated separately, the Science and the Art of Singing, it seems necessary that I should state the reasons that prompted me to this study.