jaws.]

_Endoscopy on the Human Being_.--Dog work offers but little practice
in laryngoscopy. Because of the slight angle at which the dog's head
joins his spine, the larynx is in a direct line with the open mouth;
hence little displacement of the anterior cervical tissues is
necessary. Moreover the interior of the larynx of the dog is quite
different from that of the human larynx. The technic of laryngoscopy
in the human subject is best perfected by a routine direct examination
of the larynx of anesthetized patients after such an operation as, for
instance, tonsillectomy, to see that the larynx and laryngopharynx are
free of clots. To perform a bronchoscopy or esophagoscopy under these
conditions would be reprehensible; but direct laryngoscopy for the
seeking and removal of clots serves a useful purpose as a preventative
of pulmonary abscess and similar complications.* Diagnosis of
laryngeal conditions in young children is possible only by direct
laryngoscopy and is neglected in almost all of the cases. No
anesthesia, general or local, is required. Much clinical material is
neglected. All cases of dyspnea or dysphagia should be studied
endoscopically if the cause of the condition cannot be definitely
found and treated by other means. Invaluable practice in esophagoscopy
is found in the treatment of strictures of the esophagus by weekly or
biweekly esophagoscopic bouginage.

* Dr. William Frederick Moore, of the Bronchoscopic Clinic, has
recently collected statistics of 202 cases of post-tonsillectomic
pulmonary abscess that point strongly to aspiration of infected clots
and other infective materials as the most frequent etiologic mechanism
(Moore, W. F., Pulmonary Abscess. Journ. Am. Med. Assn., April 29,
1922, Vol. 78, pp. 1279-1281).

In acquiring skill as an endoscopist the following paraphrased
aphorisms afford food for thought.

APHORISMS

Educate your eye and your fingers.
Be sure you are right, but not too sure.
Follow your judgment, never your impulse.
Cry over spilled milk enough to memorize how you spilled it.
Let your mistakes worry you enough to prevent repetition.
Let your left hand know what your right hand does and how
to do it.
Nature helps, but she is no more interested in the survival of your
patient than in the survival of the attacking pathogenic bacteria.

[126] CHAPTER XII--FOREIGN BODIES IN THE AIR AND FOOD PASSAGES

The air and food passages may be invaded by any fo