ETIOLOGY.--Inflammation of the mucous membrane, local irritation or injury, ulceration, cell-proliferation, and excessive granulation seem to be the exciting causes of benign neoplasms. They follow on laryngitis, whether catarrhal, syphilitic, tuberculous, exanthematic, toxic, or traumatic. They {128} are quite common, so to speak, several thousands of cases being on record, and as many or more probably being unrecorded. Heredity does not seem to play any special part in their production. They are occasionally congenital, and may be developed at any age; but they are encountered the most frequently in subjects between the ages of thirty and sixty years, probably because of the greater exposure to laryngitis attending the activity incidental to the prime of life. Males are affected far more frequently than females, probably on account of greater exposure to sources of laryngitis. Benign growths are sometimes followed by malign growths in recurrence, and are sometimes converted into malignity by irritation, whether physiological, mechanical, or instrumental. Malign growths are attributed to cold, chronic laryngitis, and traumatism as the initial exciting causes. Butlin suggests a cryptogamic origin. They are far more common in males than in females, and occur chiefly between the ages of twenty-five and seventy, but they have been noted as occurring exceptionally much later, and even as early as the first year. PATHOLOGY AND MORBID ANATOMY.--By far the greater number of laryngeal morbid growths belong histologically to the category of benign neoplasms, but the important location they occupy often renders them clinically malign. By far the greater number of benign growths are papillomas, perhaps fully two-thirds, although Elsberg has reported that but 163 instances were papillomas out of 310 seen in his own practice.[7] This has been an exceptional experience. Then we have fibromas, myxomas, adenomas, lymphomas, angeiomas, cystomas, ecchondromas, lipomas, and composite neoplasms. Laryngeal morbid growths, too, occasionally undergo the fatty, colloid, or amyloid degenerations. Papillomas are frequently multiple, and most frequently sessile, but the other benign neoplasms are most frequently single and are more often pedunculated. All this class of morbid growths affect the anterior half of the larynx more than the posterior. They are most frequent on the vocal bands or very near to them, although they may occupy any portion of the larynx. They vary in size from the smallest protuberance to a bulk sufficient to block up the cavity of the larynx and even project above it. The dimensions of the greater number of papillomas vary from the size of a pea to that of a small mulberry. Other benign neoplasms rarely reach the bulk attained by papillomas. [Footnote 7: _Archives of Laryngology_, p. 1, New York, 1880.]