Address by Dr. Ralph Vincent on "Production of pure milk and its value as a food for infants" : conference of representatives of public bodies and others interested in the supply of pure milk, held in the Council Chamber of the Bradford Town Hall, on Tuesday, May 21st, 1912. Councillor E.J. Smith, chairman of the Health Committee of the Bradford Corporation in the Chair.

  • Vincent, Ralph.
Date:
[1912]
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Licence: In copyright

Credit: Address by Dr. Ralph Vincent on "Production of pure milk and its value as a food for infants" : conference of representatives of public bodies and others interested in the supply of pure milk, held in the Council Chamber of the Bradford Town Hall, on Tuesday, May 21st, 1912. Councillor E.J. Smith, chairman of the Health Committee of the Bradford Corporation in the Chair. Source: Wellcome Collection.

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

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    Fig. XVI. Putrefactive bacteria growing in Milk after it has been Boiled (xi.ooo). These organisms at the time of their active growth produce the most powerful poisons that we know of—the alkaloids—and when they attack an infant or a child they generally cause death in about forty-eight hours. The next photograph shews the same milk a little later. You see in this specimen, the spores (Fig. XVII.) which have developed from the bacilli. It is the spores which are responsible for the growth of bacteria in milk that has been boiled ; for boiling destroys all bacteria, but it does not destroy the spores. These putrefactive bacteria are highly motile organisms, and they move so rapidly that they can cover 500 times their own length in one second. The photograph (Fig. XVIII.) shews you the Bacillus Subtilis, with its “ flagella ” which render it capable of this active movement. These “ flagella ” are not seen when the organism is observed under the microscope in ordinary circumstances, as they require special staining to enable them to be seen.