I made my first attempts upon a skull, to which I attached a plaster-of-Paris model of the voicebox, the whole being fastened to an iron stand. The instrument I used was a concave reflector on a spectacle frame. The reflector had a hole in the centre, and was capable of being moved in various directions. The next thing was the little mirror described on page 73, and lastly, a gas lamp on the principle of the well-known "Queen's" reading lamps, which can be raised or lowered at pleasure. I placed the skull to the left of the lamp, and looking with my right eye through the hole in the centre of the reflector, practised throwing the light swiftly and with certainty into the upper part of the throat. I then introduced the little spy mirror, and tried to see and to recognize the various parts of the voicebox, which, let it be remembered, present a somewhat different appearance in the looking-glass from what they do if seen without it. Then I got a friend to mark my artificial voicebox, unknown to me, in various ways, and endeavoured quickly to discover what he had done. In this way I soon acquired a considerable amount of skill in handling the instrument, and also became thoroughly familiar with the image of the voicebox in the mirror.[M] Having thus to a large extent mastered the mechanical part of my work, I proceeded to make observations upon myself. I placed to the left of the lamp an ordinary bedroom looking-glass, in which now appeared my own face instead of the skull which hitherto occupied this place. I opened my mouth, and by the help of the reflector directed the light into the image of it in the looking-glass. I then continued in every way as I had done with the skull, with this difference, however, that I had first, as pointed out before, to warm the little spy mirror in order to prevent its becoming dimmed in the throat.
An instrument has since been designed by the late Dr. G. D. Foulis, of Glasgow, which for simplicity, general excellence, and cheapness, far surpasses the above contrivance, and which I strongly recommend to intending students of laryngoscopy. It consists of a plain stand on which is placed a glass globe filled with water, the whole being surmounted by a small square mirror. The rays from a lamp or candle, placed behind the globe, are concentrated into the open mouth of the observer, who is seated in front of it, enabling him, by the use of an ordinary throat mirror, to inspect the movements of his own vocal ligaments.
This apparatus, as shown in the annexed drawing, including a throat mirror, and safely packed for transmission, may be had from Messrs. W. B. Hilliard & Sons, 65, Renfield Street, Glasgow, for the very small sum of 7s. 6d.
Let not the reader who tries laryngoscopic investigations be discouraged if, at first, violent retching is the result. It does not so much arise from sensitiveness of the parts touched, as from awkwardness in introducing the mirror. If he perseveres he will soon be rewarded by a view of the pearly white vocal ligaments, and a little repeated practice upon himself will enable him also to operate upon others without causing them discomfort.
I close this chapter by again reminding amateur laryngoscopists that in the vast majority of cases where the touch of the mirror causes retching and gagging, it is due less to the sensitiveness of the person operated upon than to the want of skill on the part of the operator. He should in that case renew his experiments upon himself, and continue them until he has fully mastered the use of the instrument, as it is not fair to make others suffer for his own clumsiness.
THE TEACHINGS OF THE LARYNGOSCOPE.
On introducing the mirror into the throat we first see the back part of the tongue, which has a very uneven surface, and which is, as a rule, covered with greyish phlegm. We next notice a hollow space between the tongue and the lid, which is divided by an elastic band forming a little bridge between the two. Next comes the upper free part of the lid, the shape of which greatly varies in different individuals. It hangs over the voicebox, which it almost completely hides from view; but during the production of a high tone on the vowel A, as in "sad," it takes an almost perpendicular position. When the lid is so raised ([pl. XIV], L) we can see right down to the bottom of it, where we observe that it bulges out a little. Extending from either side of the lid to the pyramids are two folds of mucous membrane, in the hinder part of either of which are to be observed two little elevations representing the cartilages of Santorini ([pl. XIV], S S), and the upper points of the wedges, called the cartilages of Wrisberg ([pl. XIV], W W). Looking down the kind of tube which is formed by the parts just enumerated, we next notice two horizontal projections running from front to back, which are the pocket ligaments ([pl. XIV], P P). Everything we have seen so far is of a pinkish colour. Below the pocket ligaments, right at the bottom of the tube described above, we see the main object of our investigation, namely, the vocal ligaments ([pl. XIV], V V). These, being almost of a pearly white, form a strong contrast to all their surroundings, and it is quite impossible to mistake them.
In quiet breathing the vocal chink is of a triangular shape, of which, however, we can only see the hinder part, the front part being hidden by the lid ([pl. XIII]). In exaggerated efforts at breathing this space gets considerably larger, so that, with a well-directed light, we can see into the windpipe, of which the rings are plainly noticeable. It is even possible to see the lowest part of the windpipe, where it is divided into the two branches entering the lungs.