August 25, 2010

The Simple Idea of Manuel Garcia

Though it is now known Manuel Garcia was not the inventor of the laryngoscope, he was the first person to use the instrument to view the vocal folds in action during singing, a monumental achievement.  What follows is an address by Manuel Garcia on how he came to see the vocal folds for the first time, and what he subsequently discovered.  His remarks are in addition to those he made (which made him famous) in 1855.

Transactions of the Seventh Session of the International Medical Congress, 
by J. W. Kolckmann, 1881, p. 197

On the Invention of the Laryngoscope
Signor Manuel Garcia, M. D. (Honoris causa), London 

Manuel García by John Singer Sargent 

To make a suitable reply to the flattering expressions addressed to me by our Chairman, and sanctioned by your approbation, would require a habit of speaking and an eloquence that I do not possess. Parvus inter magnos, I can but assure you how highly I appreciate the honour you have done me, and hope for your indulgent acceptance of my simple, sincere, and humble thanks.

In compliance with the desire which Dr. Semon was good enough to express in your name, I will tell you how the idea of the laryngoscope presented itself to me, and what were the results to which it led me. I fear, however, that this fragment of autobiography may prove a greater tax on your patience than you anticipate.

When I began to teach singing, the physiological explanations I was obliged to give to my pupils were purely empirical, and did not inspire me with any confidence as to results. At that time the vocal phenomena had been very imperfectly studied; thus, the number of registers, their extent, their individual characteristics, were not identical in the minds of all musicians. The timbres were often confounded with the registers; for no treatise of singing had yet appeared based upon anatomical and physiological considerations. In all cases instinct alone, sometimes happy, sometimes erroneous, was the only substitute for accurate knowledge.

Desirous of finding a more trustworthy guide, I began a course of anatomical and physiological studies, and the information thus acquired, added to the results of experience, were published in a method of singing; but some of the deepest and most interesting questions of plrysiology remained to me still unsolved.

I was especially anxious to find out what was the actual rule played by the glottis in the production of the voice; but where to find the necessary information?

The authors who wrote on the voice took their ideas of what the action of the healthy, living glottis might be from glimpses they caught of it through wounds, or from experiments on dead bodies, or from vivisectional researches. As for the acoustic laws that govern the movements of the glottis, every writer on the subject explained them by analogies found in musical instruments of different kinds. Thus, the stringed instruments, the reed instruments, the appeau, &c, have all served as means of comparison.

These two systems, one of induction the other of comparison, though the only systems then possible, inevitably led to different theories on the part of different observers, and could not fail to keep the mind of the student in a state of perplexity. To dissipate my own doubts, I could think of but one method—it was, to see a healthy glottis exposed in the very act of singing; but how could the mysteries of an organ so well hidden be unveiled? One September day, in 1854, I was strolling in the Palais Royal, preoccupied with the ever-recurring wish so often repressed as unrealizable, when suddenly I saw the two mirrors of the laryngoscope in their respective positions, as if actually present before my eyes. I went straight to Charriere, the surgical-instrument maker, and asking if he happened to possess a small mirror with a long handle, was informed that he had a little dentist's mirror, which had been one of the failures of the London Exhibition of 1851. I bought it for six francs. Having obtained also a hand mirror, I returned home at once, very impatient to begin my experiments. I placed against the uvula the little mirror (which I had heated in warm water and carefully dried): then, flashing upon its surface with the hand mirror a ray of sunlight, I saw at once, to my great joy, the glottis wide open before me, and so fully exposed, that I could perceive a portion of the trachea. When my excitement had somewhat subsided, I began to examine what was passing before my eyes. The manner in which the glottis silently opened and shut, and moved in the act of phonation, filled me with wonder. From what I then witnessed, it was easy to conclude that the theory which attributed to the glottis alone the power of engendering sound was absolutely confirmed, from which it followed that the different positions taken by the larynx in front of the throat have no action whatever in the formation of sound; although, combined with divers elevations of the soft palate, they change the shape and the dimensions of the pharynx. In these changes we find the means of varying the qualities of the voice known as timbres or Farbenklange.

I also perceived that vocal sounds are the results of explosions, not of communicated vibrations. This is proved by the fact that each separate lip of the glottis is incapable of producing any kind of sound. Besides, the lips do not protrude sufficiently to form vibrating reeds; and, if protruding, how could they vibrate in spite of recurring contact with each other?

Having thus seen the vocal organ in action, I next began to study the mechanism of the scale. This mechanism has two aspects—an exterior movement, visible with the mirrors; and an internal cause of that movement, which anatomy alone can explain. The exterior movement becomes manifest in the development of the scale. Beginning from the lowest note, the glottis is put in motion throughout its whole length; but as the voice rises, the anterior apophyses are gradually pressed closer by a movement which spreads from back to front, and they arc alternately in close contact. These continuous encroachments diminish the vibrating portion of the glottis until it becomes reduced to the ligaments alone.

The internal cause resides in the intrinsic muscles; and, among these, that which coats the outer surface of the crico-thyroid membrane—namely, the thyro-ary tenoid muscle—was to me of the greatest interest. The fibres of which it is composed, although all starting from the anterior and lower cavity of the arytenoid cartilage, are not all of equal length. The most internal are the shortest. Each successive fibre becomes progressively longer and terminates in a more distant point of the ligament; the longest and most external only reaching the thyroid cartilage. From this remarkable disposition, it follows that only the shortest fibres contract for the deepest notes, and, as the voice ascends, successive fibres come accumulatively into play.

To complete the subject, I ought to speak of the action of the other intrinsic muscles; but that has been already treated in the pamphlet read at the Royal Society in 1855. In the same paper I have also expressed my ideas as to the formation of the registers. If I have spoken somewhat in detail of the thyro-arytenoid muscle, it is that its special characteristics—the unequal length of its fibres and their insertion in the ligaments—have been disputed. But before venturing to represent as fact this result of my observations, I wished to make sure that I had not been mistaken; and, therefore, consulted Professor Thane, who, with a cordial interest for which I cannot sufficiently thank him, not only examined the contested point, but presented me to Mr. Shattock, begging him to assist me with his experience.

This is the drawing which that most skilful anatomist has been good enough to make for me. It entirely confirms the view which I have had the honour to place before you. I will not trouble you with further details.

The laryngoscope in itself is not an invention—it is a simple idea; and when I suggested to Dr. Mandl and to Dr. Segond that they should test its usefulness in the practice of healing, I was far from anticipating the brilliant future your science and skill reserved for it.

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