The subject was at once taken up with great activity, especially in Vienna, where success was far from equalling the hopes of the doctors. The caprices of solar light and the defects of artificial threw them into a state of despair. By all means they must improve their mirrors. Czermak, the Professor of Physiology at Pesth, taking an example from the instrument used in examining the eye, the ophthalmoscope, had recourse to a concave mirror which concentrated the light. From this time there was no difficulty but to perfect the lenses. Czermak having acquired great skill in the use of his laryngoscope, visited the principal cities of Germany, where his demonstrations deeply interested surgeons and physiologists. He was warmly received in Paris in 1860, where he shewed not only the whole length of his larynx, but also the interior of the trachea or windpipe as far as its bifurcation; a spectacle truly astonishing to those who witness it for the first time. It is not possible to examine the organ of the voice with the same facility in all; a man must have had some experience before he can do it.
A slight sketch of this organ will perhaps make the subject clearer. From the breast there rises to the middle of the neck the passage for the air between the lungs and the mouth; at one end it is divided into numerous branches, called the bronchial tubes; at the upper end, like the capital of a column, is seen the larynx, resembling an angular box; strong cartilages make it very resistent; and the interior is lined with a mucous membrane forming folds, named the vocal lips. These separate, lengthen, or shorten in the formation of various sounds. The largest of the four cartilages rises in an annular form, and protects the whole structure. It is but slightly shewn in the neck of the female, but strongly marked in the man, and is popularly called Adam's-apple. Like everything else, the larynx presents individual differences. A fine development is an indication of a powerful voice. As the child grows up, there is a sudden alteration and increase of size; but it always remains smaller in the woman than in the man; the angles are less sharp, the muscles weaker, the cartilages thinner and more supple, which accounts for the sharp treble notes in their voices.