of the true tubercular phthisis, but, in this case, almost always before the age of 25. We occasionally observe chronic bronchitis in the young miner, but by far—far more frequently between the ages of 36 and 50.
"Miners are subject to every degree of dyspnœa up to the most confirmed asthma, to spitting of blood, hydro thorax, general dropsy, valvular and other disease of the heart and great vessels, &c. The last-named class of diseases are often the cause of the others, by deranging and obstructing the pulmonary circulation, occasioning extreme congestion, and even regurgitation of the blood, and thereby giving rise to organic lesion of the pulmonary tissue with all its consequences—inflammation, effusion, thickening, adhesion, rupture, &c. &c.
"The more than ordinary frequency of diseases of the heart and its great vessels, and of the whole pulmonary organs, in miners, I am, from long observation, convinced, may be fairly attributed to their occupation; but not so much to their actual labour, or to the impure air in which they sometimes work, as to the hasty and imprudent manner in which they too often climb the ladders in ascending from the mines. On these occasions so distressed are they who have been so inconsiderate, on reaching the surface, from the inordinate action of the heart, and consequent hurried and crowded circulation of blood through the lungs, as to be unable for some minutes to speak. It is very true they are not necessarily compelled to ascend so rapidly; but still, such is the force of emulation, as I have learnt from frequent conversations with captains of mines, and the men
