238 ATMOSPHERE IN RELATION TO HUMAN LIFE AND HEALTH. 



skin, and starch. Even coal gas, which shows no smoke in its com- 

 bustion, fills the air where it is burnt with millions of particles in 

 every cubic foot. The whole atmosphere is pervaded by particles of 

 salt derived from the spray of the seashore and of ocean waves. In 

 summer, pollen seeds, odors of earth, trees, flowers, and hay, and the 

 spores of an immense variety of fungi float on every breeze. Most of 

 these have no special interest, but some of the spores and pollen are 

 capable of setting up great irritation in the human system, almost 

 amounting to diseases. Hay fever is the result of the action of grass 

 pollen on the breathing passages. 



LIVING GERMS IN THE AIR. 



Much more important are the living germs, the microbes, bacteria, 

 fungi, and molds, which are found very unevenly distributed, and 

 especially abundant at low levels in populous places and habitations. 

 Miquel found in a cubic meter at Montsouris Observatory, near Paris, 

 85 of these organisms in spring, 105 in summer, 142 in autumn, and 49 

 in winter. On other occasions the numbers were 70, 92, 121, and 53, 

 respectively. 



In the Rue de Rivoli, in Paris, the number was about 5,500. In air 

 collected at 2,000 to 4,000 meters high (about 6,300 to 13,600 feet) no 

 bacterium or fungus spore was found. Pasteur exposed 20 flasks of 

 clear broth in the open country of Arbois, 20 on the Lower Jura, and 20 

 near the Mer de Glace, at a height of over 6,000 feet. Of the Arbois 

 flasks, 8 developed organisms ; of the Jura, 5; and of the Mer de Glace, 

 1 only. 



Miquel's experiments proved that microbes were much more abun- 

 dant in the town than in the country. In rooms the number was eight 

 times, and in hospitals twelve times the number in the open air. These 

 experiments refer to hospitals in Paris only. In hot countries, after a 

 prolonged period of dry hot weather, microbes diminish. In M. Miquel's 

 view the places where there are most microbes are centers of infectious 

 disease ; the curves of mortality to a great extent correspond with the 

 curves of the number of microbes and follow them after a short interval. 

 In 1 gram of the dust of his laboratory he found 750,000 germs, and 

 in that of a room in Paris 2,100,000. In the air of hospitals microbes 

 of suppuration have been found. Devergie found an "immense amount'' 

 of organic matter in the- air in the vicinity of a patient with hospital 

 gangrene. Dr. Dundas Thompson found, in the air of a cholera ward, 

 starch, woolen fibers, epithelium, fungi, or spores of fungi, and vibrioues. 

 Scaly and small round epithelia are found in most rooms, and in large 

 quantity in hospitals. The dust of a hospital ward at St. Louis con- 

 tained 36 to 46 per cent of organic matter, largely epithelium cells. 

 Parkes similarly detected large quantities of epithelium in the air of 

 barracks and hospitals. In 1 gram of dried earth Miquel found 

 800,000 to 1,000,000 microbes. Recent research shows the number is 



