For a second sitting one should secure at least two specimens of the larynx of the pig or sheep, though the former is more like the human, and so the better on the whole. A case of dissecting instruments is not essential; a sharp pocket-knife will serve the purpose. In order that the student may have a clear idea of the cartilages, all the soft tissues must be cut or scraped away. It is necessary to exercise great care, or the membranes connecting the cartilages together will be cut through; and on the other hand, unless the work in the neighborhood of the arytenoids be cautiously done, these cartilages may be injured, and it is most important that their swivel-like action and their relations to the true vocal bands be observed. The glottic chink can be seen from above or below, and should be observed from both view-points. Its margins are formed by the true vocal bands. Then, with the figures before him, the student should endeavor to isolate each of the muscles described. The muscles can always be recognized by their red color, but it is to be remembered that those on the inner surface of the larynx, such as the crico-arytenoid, are covered with mucous membrane, which after death is very pale. This can by careful dissection be removed, and if in doing this a small pair of forceps be employed, the work will be greatly facilitated. One must be very skilful indeed if he would get all the muscles "out," or well exposed to view as individuals, on a single specimen. Likely several will be required before entirely satisfactory results are reached, but these are well worth all the time and labor required. The action of the muscles can in some measure be demonstrated by pulling on them in the direction of their loosest attachment, though it must be confessed this is much more difficult in the case of most of the muscles of the larynx than in those of other parts of the body. Should the specimens be very successfully dissected, it may be worth while to keep them for future observation, in rather weak alcohol (40 per cent.), in, say, a preserve jar. All examinations of the vocal bands may leave the observer disappointed; he may fail to realize, most likely, how such wonderful results can be accomplished by structures so simple as those he sees before him. But when the laryngoscope is brought into use, then comes a revelation. This instrument will be described in the next chapter. HYGIENE.