In the daily routine of practice, probably there is no affection more frequently met with by physicians than coughs, and in many cases they are puzzling, harassing and stubborn.
Even after nearly the whole range of indicated pharmacopeial medicines have been applied, the cough still remains as before, excepting with temporary relief. The patient becomes alarmed, fearing pulmonary complications, although assured by the physician that no lesions or symptoms exist in that region.
Mayo Collier1 says that "cough as a symptom or indication of some irritation in the upper or lower respiratory tract or other parts, is the commonest affection the human frame is subject to." Such cough, however, is oftener extrapulmonary in origin and quite innocent in its nature, and a highly commendable service is rendered and the dignity and scientific value of medicine exhibited when, by thorough and accurate examination, the extraneous cause is discovered, skilfully removed
MILBURY FS. COUGH DUE TO REFLEX IRRITATION IN THE UPPER AIR-PASSAGES.. JAMA. 1901;XXXVI(21):1475–1477. doi:10.1001/jama.1901.52470210025002h