4 THE POPULAR SCIENCE MONTHLY. 



east or west, the death-rate from lung-diseases was found to bear an 

 exact proportion to the percentage of the inhabitants habitually en- 

 gaged in sedentary and in-door occupations. Towns suffer more than 

 the rural districts, cities more than country towns, manufacturing cities 

 more than commercial and semi-agricultural cities, weaver-towns more 

 than foundry-towns. " If a perfectly sound man is imprisoned for 

 life," says Baron d'Arblay, the Belgian philanthropist, " his lungs, as 

 a rule, will first show symptoms of disease, and shorten his misery by 

 a hectic decline, unless he should commit suicide." 



Moreover, it was shown that in non-manufacturing (uncivilized or 

 pastoral) regions a low temperature seems to afford a protection against 

 pulmonary disorders. Professor Jacoud found that, at an elevation of 

 four thousand feet, the cold Alpine districts of Northern Savoy are 

 almost free from lung-diseases. The medical statistics of the Austrian 

 army have established the fact that recruits from the Tyrol, from 

 Carinthia, and the Carpathians (Transylvania), i. e., from the highest, 

 and consequently the coldest, provinces of the empire, enjoy a re- 

 markable immunity from tubercular consumption. Dr. Hjaltelin, a 

 resident of Iceland, states that among the inhabitants of that country 

 pulmonary diseases are almost unknown. 



But in the temperate zone consumption-statistics alone would en- 

 able us to infer the amount of dust-breathing and in-door work inci- 

 dental to the pursuit of each trade. In the Italian cities that have 

 largely engaged in the production of textile fabrics, consumption has 

 become as frequent as in Lancashire. Irrespective of race-differences 

 and special dietetic habits, the habitual breathing of vitiated air leads 

 to the development of pulmonary scrofula. And science has furnished 

 the rationale of that result. Physiology has demonstrated that air is 

 gaseous food, and respiration a process of digestion. The atmosphere 

 furnishes the raw material of the pulmonary pabulum ; at each inspi- 

 ration the organism of the lungs imbibes the oxygenous or nutritive 

 principle of the air-draught, and excretes the indigestible elements. 

 By breathing the same air over and over again, the atmospheric ali- 

 ment becomes azotized, i. e., depleted of its life-sustaining principle, 

 and therefore unfit to supply the wants of the animal economy. The 

 continued inhalation of such vitiated air fills the respiratory organs 

 with indigestible elements, which gradually accumulate beyond the 

 dislodging ability of the vital forces, and at last corrupt the tissue of 

 the congested organ and favor the development of parasites. Con- 

 sumption is one of the diseases that seem to confirm the tenets of the 

 germ-theory. A tubercular diathesis is favored by stagnant impurities 

 of the circulatory system, by a warm and humid climate, and counter- 

 acted by cold air and other antiseptics. Six years ago a German phy- 

 sician demonstrated that the progress of pulmonary scrofula can be 

 arrested by a pectoral injection of carbolic acid ; and one of his coun- 

 trymen lately ascertained that the tubercle-virus is alive with micro- 



