Licence: Public Domain Mark
Credit: The atmosphere in relation to human life and health. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![as Western Kajpootaiui, are subje(!t to miliaria, althouj^h the water is several hundred feet below the surface, liut here the sand is found to be dani}) a short distance below the surfa(;e, and probably the same condition ju'evails elsewhere in sandy tra(;ts where malaria is ])resent. The rainfall is scanty, but the great range of temi)erature ])robably causes a good deal of dew-condensation on the sand. Sometimes, though rarely, rocky surfaces emit malaria, but ])rol)ably the habitat of the organisms in these cases is in clefts or disintegrated rocky detritus. The eflicieney of attack 07i the human body depends in great measure on the concentration of the organisms within a fciW feet of the surface of the eartli in the evening hours, the diirereiice between day and night temi)erature, the high temperature of the soil, and the suddenness of the fall of temperature. Although the strong- est men in the best of health nuiy be stricken, yet, in most nuilariuus countries, the avoidance of fatigue, of indigestion, and of any chilling of the surface of the body, is an important safeguard. The conditions in which malarious germs are emitted from the soil and concentrated in the nethermost strata of the air are further considered in relation to the emanation of vajior from the earth and the deposition of dew. YELLOW FEVER. Yellow fever results, in all probability, from a fungoid or raicrobic growth, but the jiarticular microbe concerned has not been certainly identified. It prevails habitually in the West Indies and on the coasts of the Gulf of Mexico, and these have been regarded as the original breed- ing grounds. But it has also long been endemic on the west coast of Africa, especially at Sierra Leone. It is easily capable of transi)orta- tion, especially in the case of particular outbreaks and in particular seasons, and it has in several years, like cholera, attained almost a world-wide prevalence. When transplanted to favorable places (and these are mostly seaports with very poor sanitary conditions) it takes root and breaks out in succeeding years as if it were multiplying on the polluted soil. As a matter of fact, it thrives on damp organically contaminated soil, on the walls of houses, and on the wood of ships, in foul holds. It haunts the vicinity of drains, banks of rivers occasion- ally dry, harbors, and crowded rooms or houses. The manner of its growth a good deal resembles that of cholera, but its areas of iireva- lence are smaller, and it is more largely communicated through the air, each case of yellow fever becoming a focus of prevalence in tropical and foul conditions. It requires a high temperature for its propaga- tion, and is arrested, but not destroyed, by frost. Strangers are much more liable to attack than residents, but residents are not always immune. The living cause of the disease clings with great tenacity to ships, walls, etc., for a long time, and is conveyed, in very many instances, by tlie air to persons who approach the infected object. The organic poison seems to multiply outside the body, upon foul surfaces,](https://iiif.wellcomecollection.org/image/b21208724_0075.jp2/full/800%2C/0/default.jpg)
