Dyspnea, or the labored breathing of miners' phthisis, as it was called, was well known to patient and doctor alike long before the word silicosis was coined.
The crux of the problem of what causes the dyspnea of silicosis is well illustrated and described in figures 1 and 2 with their elaborate captions.
Dyspnea is the outstanding symptom of silicosis, yet in our opinion it has not been accounted for by hitherto recognized pathologic changes. Dyspnea is the prime factor that incapacitates the worker for hard labor and subsequently for any labor, and it is dyspnea that eventually terminates the victim's sufferings, yet dyspnea is singularly absent in many cases of well marked silicosis in which there are classic roentgenographic signs. It is universally conceded that small, hard, dense nodules in the lung are pathognomonic of silicosis, yet these small, hard, dense nodules are either absent or relatively infrequent in