On continuous molecular changes, more particularly in their relation to epidemic diseases : being the oration delivered at the 80th anniversary of the Medical Society of London / by John Snow.

  • Snow, John, 1813-1858.
Date:
1853
Catalogue details

Licence: Public Domain Mark

Credit: On continuous molecular changes, more particularly in their relation to epidemic diseases : being the oration delivered at the 80th anniversary of the Medical Society of London / by John Snow. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    8/46 (page 2)
    The principal forces with which we are acquainted are, the attraction which the atoms of matter exert on each other at all distances, and the attraction which exists only at insensible distances. The first of these forces is called the attraction of gravitation; and the term chemical attraction, or chemical affinity, includes more or less of the second force, according to the more or less extended sense in which the word che- mistry is understood. The eflfects of gravitation on living beings are of a simple kind, and are pretty well known; therefore they need not detain us. With respect, however, to the attraction which takes place at insensible distances, the case is diflPerent. The results of this attraction in living beings are very complicated and important, and they require much in- vestigation.- The attraction of gravitation is a constantly ope- rating force, even when it leads to no relative change of position; and in like manner the attraction at in- sensible distances is equally constant in its action under all circumstances, whether it is causing changes of composition and arrangement, or merely holding to- gether the particles of a metal, or preventing changes in a compound body, by a balance of affinities. The attraction amongst adjoining particles of matter may be very feeble, but it is probably never altogether absent. Eminent chemists tell us, indeed, when speaking of atmospheric air, that the nitrogen mani- fests no attraction for the oxygen, and that all