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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![jfrom the constant presence, and, as it were, the vaccinating influence, of the germs in bad air. From similar reasons horses, when brought from the country to London stables, very frequently fall out of sorts to the extent, it is said, of 95 per cent, and sheep, when placed among imported apparently healtliy sheep, often fall sick. Texas cattle fever is caught from apparently healthy cattle. The first intercouse between Europeans and natives is attended with the introduction of fever, dysentery, or other diseases.^ SEASONAL AND GEOGRAPHICAL DISTRIBUTION OP INFECTIOUS DISEASES. Many of the spreading diseases are more or less wont to rise toward a maximum and to fall toward a minimnm at certain times of the year, and these seasons are generally nearly the same in similar climates in the same hemisphere, but there are many particular instances of variation. Scarlet fever is a disease chiefly jDrevalent in the northwest of Europe, moderately prevalent in Russia, North America, and parts of South America, the coast of Asia Minor, Italy, Tur]i:ey, and Greece, and quite uncommon in Asia and Africa. It is not frequent in Australia. Its maximum in London occurs in October, its minimum in April. In New York its maximum is in April, its minimum in September. In Eng- land, generally autumn is the time of maximum prevalence. In the whole of Europe and North America 29.5 per cent out of 435 epidemics are recorded as having occurred in the autumn, and 21.8 per cent in the spring, the period of minimum; the remaining 48.7 per cent took place in summer and winter. A dry air with little rain seems to increase the prevalence of scarlet fever. Measles, in London, has two maxima, one in December and a lesser one in June, and two minima, one in September and one in February. Measles occurs nearly all over the world since the great extension of commerce, and seems to be little afiected by climate. Cold weather, however, favors it, as might be expected, since it infects through the air of close rooms. Influenza, typhus, relapsing fever, smallpox, whooping cough, croup, pneumonia, not only prevail most in cold weather, but in cold countries, where there is least outdoor life and least fresh air in rooms and most crowding. Diphtheria increases with the cold weather of autumn, but tends to decline in February, and is at a minimum during the hot months. Cerebro-spinal fever, which is a good deal connected with crowding in large numbers in institutions, etc., not only attacks most in cold weather, but in cold or temperate countries. The relation between the temi^erature and the disease seems to be indirect, and the causation and dissemination of the malady are obscure. 1 Williams, quoted by Darwiu, Naturalist's Voyage.](https://iiif.wellcomecollection.org/image/b21208724_0084.jp2/full/800%2C/0/default.jpg)
