Public health laboratory work / by W. Watson Cheyne, W.H. Corfield and Charles E. Cassal.

  • Watson Cheyne
Date:
1884
Catalogue details

Licence: Public Domain Mark

Credit: Public health laboratory work / by W. Watson Cheyne, W.H. Corfield and Charles E. Cassal. Source: Wellcome Collection.

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    a living body. One of the best examples of this is the bacillus of tubercle, which, though it can be artificially cultivated outside the body under special conditions, can seldom if ever meet with these necessary conditions in nature. The following are the chief steps required for the proof that a given organism is the cause of a disease. Firstly, an organism of a definite form and with definite character- istics must always be found in the blood or in the affected parts of the animal body. The blood or the affected parts containing these organisms, when inoculated into another animal of the same species, must produce the same disease. Treatment of the blood or affected parts in such a manner as to destroy the micro-organisms present in them must also destroy their power of causing disease in another animal. When the diseased parts are inoculated on suit- able soil outside the body the micro-organisms grow, and can be indefinitely propagated on similar soil.* When in this manner the organisms have been separated from the remains of the animal substances in which they were imbedded, their inoculation on a suitable animal must again produce the disease, the same organisms being also found in the diseased parts. This sort of proof has now been furnished for a considerable number of diseases. The best known example of a disease due to micro- organisms in which the above proof has been furnished is that of anthrax or splenic apoplexy. This disease affects all mammalia, including man, and birds are also liable to be attacked by it. It may commence by the formation of a pustule of a carbuncular nature, but usually, especially when the disease is rapid in its course and the animal is particularly liable to it, no pustule is observed. Some- times animals are suddenly struck down while apparently well, but generally the temperature becomes high, they stag-ger, bleed from the nose, mouth, &c., and rapidly die. * The cultivation of some pathogenic organisms, for example of leprosy, and relapsing fever, has not yet been successful, but it is necessary for the absolute proof that they are the causes of these diseases.
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