IV. Another question is this: Which part of the complex of symptoms described here was caused by the presence of coal particles in the pulmonary parenchyma? At his admission, the patient claimed that he had been suffering from a cough and sputum for twenty years. Since he did not start working in the coal dust until 1848, those manifestations can be related only to a simple catarrh that was already present before this time. Interpreting the shortness of breath is already more uncertain, since it did not join the cough and sputum until later. It is possible that the patient might have been able to provide more precise information about the time this manifestation appeared; unfortunately, I neglected to ask him about it. The illness that afflicted him three and a half months before his admission was, as the autopsy determined, a pericarditis, later complicated by a bilateral pleuritis. This affection was undoubtedly the source of the orthopnoea, the irregular heart action, the changes presented by the urine, the cyanosis, and the hydropsy. For these are manifestations that have been frequently observed in simple cases of insidious pericarditis. Of the symptoms that can be related to the accumulation of coal particles in the pulmonary parenchyma, we are thus left only with the peculiar cough, my explanation for which is that as a result of the increased secretion of fluid in the pulmonary alveoli, coal particles were being constantly driven into the bronchia, where they had an irritating effect on the mucous membrane because of their angular and pointy shape. Of course, this explanation presupposes that the reflex movements of the cough cannot be triggered by the pulmonary parenchyma, but that does in fact accord with other clinical facts. The explanation for why the cough stopped at the end seems to me to be that under the influence of the increased intestinal secretion, the abnormal secretion in the pulmonary alveoli was arrested. In fact, the sputum became very sparse precisely around that time.
V. Another question of clinical importance is whether exposure to a dusty atmosphere is sufficient by itself to cause the accumulation of particles in the pulmonary alveoli. If one considers how many people spend all their time in such an atmosphere without presenting any manifestations that their respiratory apparatus is affected, the assumption virtually thrusts itself upon us that this condition must be joined by a second one. The circumstance emphasized above, that our patient had been suffering for some time from a bronchial catarrh when his work at the coal yard began, seems an indication to me that a disturbance in the mechanism of ciliary action may be this second condition, in that either the movement of the cilia is impeded by the coating of phlegm, or their effectiveness is reduced because of deficient alimentation of the cells that carry them.