Very often the inclination to pulmonary consumption may be recognized from the external characteristics. As a rule the respective individuals have a slight body, thin lean skin, weak muscles, delicate skeleton, a long, narrow, flat chest, flattening of the regions over and below the shoulderblades, wide intercostal spaces, a winglike projecting of the scapulæ, long neck, clubby, knoblike appearance of the ends of the fingers.
Furthermore it has been found, that pulmonary consumptives on an average have a smaller heart than is essential to a healthy body. On the other hand the volume of the lungs of consumptives is very often abnormally large.
There are a large number of diseases that predispose to pulmonary consumption. It is mainly the enfeebling action of the same, which brings about such results. For this reason the chronic diseases contribute so much toward the multiplication of the number of consumptives, because they stipulate a continuous weakening of the organism and an emaciation of the system. To these belong Bright's disease, which very often turns into pulmonary consumption, greensickness or chlorosis, anaemia, continued febrile diseases, severe chronic suppuration, chronic catarrh of the stomach, frequent pregnancies, childbed diseases. Thus we may often see young chlorotic girls afflicted with consumption, especially when they marry young and enjoy the honeymoon to its utmost limits. Then also women will easily become consumptive when they give birth to a child every year, especially when the social conditions in which they live are of an unfavorable nature, and they are perhaps inclined to consumption already. Childbed on the whole inclines to arousing the dormant inclination toward pulmonary consumption.
Of other diseases we have mentioned measles and whooping cough, as diseases that are only too easily succeeded by consumption. To these may be added typhus, especially when it is of a more protracted nature, and the reconvalescence is slow and incomplete.
Furthermore all those workmen that have to do with dust, are exposed to the danger of being stricken with pulmonary consumption. The dust enters the lungs, irritates and injures the same and so produces a favorable soil for any tubercle bacilli that may happen to penetrate. On the whole metal dust is more injurious than mineral dust. Workmen, that are exposed to animal dust, as furriers, saddlers, brushmakers, fall prey to consumption much oftener than those, that fulfill their vocation in air pregnant with vegetable dust. According to statistics workingmen are stricken with pulmonary consumption as follows: of glass workers 80 per cent., needle grinders 70, filemakers 62, stone cutters 40, mill grinders, lithographers, cigarmakers, brushmakers, stone-polishers 40–50, millers 10, coal workers 1 per cent.
Pneumonia may culminate in pulmonary consumption: but on the whole this rarely happens. Much oftener it is the case with Pleurisy. But it is assumed and rightly, that most people who are attacked by pleurisy, are already consumptive.
A hemorrhage of the lungs may nearly always be considered a sure sign that consumption has taken hold of the respective individual; but such a hemorrhage certainly forms considerable danger to falling a victim to tuberculosis, if the individual is as yet free from the same.
Age has a particularly decided influence on the origin of consumption; it is extremely rare before the third or fourth year, from that to the seventh it is more frequent; it most frequently occurs in the age from the fifteenth to the thirtieth year, and from there on the chances are again fewer. In very old age it is again very rare.
There seems to be no essential difference as regards sex.
Insufficient or defective nourishment acts as a promoter in various ways. Even the nourishing of infants with poor milk, with bread or flour-pap increases the disposition to pulmonary consumption. If this defective nourishment is continued, scrofula will surely follow and this is a stage antecedent to consumption.