Epidemiology; or, The remote cause of epidemic diseases in the animal and in the vegetable creation / by John Parkin.

  • Parkin, John, 1801-1886.
Date:
1886
Catalogue details

Licence: Public Domain Mark

Credit: Epidemiology; or, The remote cause of epidemic diseases in the animal and in the vegetable creation / by John Parkin. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

    45/378 (page 39)
    microscopist — that they are not morbid, but merely healthy particles of the vital fluid, or the blood. What has been said by one writer, respecting the cattle plague, will probably hold good with respect to all other diseases to which this theory has been applied. Dr. Beale has examined portions of infected blood, textures and mucous discharges, with the highest magnifying powers that exist, viz., one-fifth of an inch focal adjustment. This magnifies 2,800 diameters; or, to express the magnifying power by some examples, an inch would appear to extend over 111 yards, and a child three feet tall would look as high as Mont Blanc. With such power, particles of even l-100,000th of an inch in diameter, having any distinct character, would not be passed over. But he has found no definitely formed substance that can certainly be said to be the cause of the cattle plague. He finds a great increase of granular matter, but no new appearance decidedly characteristic of the disease. * Like the former theorists, the advocates of this doctrine dwell much on the circumstance that it offers a ready explanation of the presumed increase of the virus within the body. But the explanation thus offered in support of the doctrine, the same as that advanced for the fermenta- tion theory, is fatal to it. If these organisms can and do reproduce themselves, when present in the blood, in the tissues, and in the secretions, there can be nothing to prevent their self-multiplication, ad infinitum, short of their destruction or that of the patient. As it would be folly to suppose that these germs could be destroyed by any means with which we are at present acquainted, if it be true that a cubical inch of water, and, consequently, of blood, can contain millions of particles, they would go on increasing as long as any pabulum—the nutrient portion • Thh-d Report of the Cattle Plague Commissioners, p. vi.