Variola, vaccination, varicella, cholera, erysipelas, whooping cough, hay fever / by H. Immermann [and others] ; edited with additions by John W. Moore ; authorized translation from the German, under the editorial supervision of Alfred Stengel.

  • Immermann, H.
Date:
1902
Catalogue details

Licence: In copyright

Credit: Variola, vaccination, varicella, cholera, erysipelas, whooping cough, hay fever / by H. Immermann [and others] ; edited with additions by John W. Moore ; authorized translation from the German, under the editorial supervision of Alfred Stengel. Source: Wellcome Collection.

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    opportunity of reducing the facts to a mathematic expression. According to A. Wynter Blyth, the influence of the Sheffleld Hospital could be dis- tinctly traced for a circular distance of 4000 feet. Whether the contagious particles are conveyed by the air itself, or by the medium of the common household fly or other insects, the important fact remains that the infec- tion can strike at a considerable distance, though with less certainty as the distance increases from the infective center or focus of the disease. F. AV. Barry, Inspector of the Local Government Board for England, found the following percentages of households attacked at successive distances from the Sheffield Hospital: 0-1000 Feet. 1000-2000 Feet. 2000-3000 Feet. 3000-4000 Feet. Elsewhere. 1.75 0.50 0.14 0.05 0.02 At Bradford, in 1893, Arnold Evans confirmed Dr. Barry’s conclusions, but he went fui’ther. A study of the direction of the prevailing winds throughout the year 1893 supplied him with evidence strongly confirma- tory of the view that the poison was conveyed aerially direct from the wards of the hospital. Dr. Evans selected a one-mile area around the hospital and divided it into quadrants by drawing radii to north and south, to east and west. He found that in the northeast quadrant 7.06 ^ of the houses were infected ; in the northwest quadrant, 2.40^; in the southeast quadrant, 5.28^; and in the southwest quadrant, 2.93^. The percentage of infected houses in the special zone east of the hos- pital was 5.6, compared with 2.9 on the west side. These figures are easily explained by the fact that westerly winds prevailed on two hundred and fifty days in the year, easterly winds on only eighty-three days. During the fii’st half of the year, when easterly winds were more common than during the second half, the proportion of cases occurring on the western side of the hospital was relatively greater than during the remainder of the year, when east winds were less frequent.] The contagiousness is, however, by no means dependent on the exist- ence of the exanthem, as smallpox has been repeatedly transmitted to the healthy before the eruption appeared (in the initial period), and even toward the end of the period of incubation. Even in those interesting cases of variola sine exanthemate, which are characterized by the absence of a typical eruption, there is danger of infecting others, and this danger is also present during the healing of the exanthem as long as crusts and scabs are found on the body of the convalescent. It follows from all that has been said that smallpox is infectious by means of a volatile contagium, in every stage of the disease (without exception), but that the different stages, of course, show quantitative difference in this respect.