Fragments of science : a series of detached essays, addresses, and reviews / by John Tyndall.

  • John Tyndall
Date:
1876
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Licence: Public Domain Mark

Credit: Fragments of science : a series of detached essays, addresses, and reviews / by John Tyndall. Source: Wellcome Collection.

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    muddy or cloudy on the llth. Thus, doubtless, in a con- tagious atmosphere, are individuals successively struck down. On the 12th all the tubes had given way, but the differences in their contents were extraordinary. All of them contained Badena, some few, others in swarms. In some tubes they were slow and sickly in their motions, in some ajoparently dead, while in others they darted about with rampant vigour. These differences are to be referred to differences in the germinal matter, for the same infusion was presented everywhere to the air. Here also we have a picture of what occurs during an epidemic, the difference in number and energy of the Bacterial swarms resembling the varying intensity of the disease. It becomes obvious from these experiments that of two individuals of the same population, exposed to a conta- gious atmosphere, the one may be severely, the other lightly attacked, though the two individuals may be as identical as regards susceptibility as two samples of one and the same mutton-infusion. Experiments with other trays are described in the full account of this investigation, and calculations are made which prove the error of the assertion that the germs are but scantily distributed through the air. There are billions of them in every ordinary London room. The parallelism of these actions with the progress of infectious disease may be traced still further. The 'Times' of January 17 contained a letter on typhoid fever, signed ' M.D.,' in which occurred the following remarkable statement: 'In one part of it [Edinburgh], congregated together and inhabited by the lowest of the population, there are, according to the Corporation return for 1874, no less than 14,319 houses or dwellings—many under one roof, on the 'flat' system—in which there are no house connections whatever with the street sewers, and, consequently, no water-closets. To this day, there- b