This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
In acute stages of pneumonia, bronchitis, or pleurisy, the acetate or citrate of ammonia is often serviceable. In asthenic cases, the later chronic conditions of bronchitis, and in senile catarrh, the carbonate and liquor are good stimulant expectorants, being eliminated in part by the pulmonary membrane, they modify its condition and thin the secretion. Ammonium chloride is also valuable in such conditions, and in asthenic lung-congestions: it may at first increase pyrexia, but generally facilitates the expectoration, "softens the cough," and improves appetite. Dr. Patton has written to commend the carbonate in acute pneumonia, and the chloride in later stages (Practitioner, vol. vi.).
In the bronchitis of measles, and of rachitis, ammonia is commonly and advantageously used, - Sir W. Jenner, indeed, speaks of it as the remedy in the lung-affections of the latter malady, which are generally asthenic and tend to collapse (Medical Times, i., 1860). On the other hand, Dr. Eustace Smith maintains that if too early given to children with bronchitis it may determine even a fatal issue (Medical Times, i., 1873).