Principles of general physiology / by Sir William Maddock Bayliss.

  • William Bayliss
Date:
1924
Catalogue details

Licence: In copyright

Credit: Principles of general physiology / by Sir William Maddock Bayliss. Source: Wellcome Collection.

    48/956 page 10
    violet light when impinging on various substances is observed by the microscope. The colour of the light emitted by these fluorescent substances differs according to their composition, so that it may be possible to detect the presence in the living cell of substances otherwise invisible. Further information will be found in Chapter XIX., and in the papers by Stiibel (1911), and by Heimstadt (1911). Fig. 10. 1 and 2. Dividing nuclei from gill plate of Salamander larva. Unstained, in glycerol. Photo¬ graphed with ultra-violet light of 280 fx/x. The chromatic substance appears as if stained. 3. Edge of sternal cartilage of Newt. Living. Photographed with ultra-violet light. The nuclei are opaque. 4. The same. Photographed with ordinary light. The nuclei are transparent. 5. Red blood corpuscles of the Newt. Living. Photographed with ordinary light. Although oblique illumination was used, the nuclei are almost invisible. Traces' of diffraction are seen around the corpuscles. 6. Amoeba. Living. Photographed with ordinary light. The nucleus is just visible, but transparent. (Nos. 1 to 3 after Kohler.) INTRA-VITAL STAINING The second method, that of staining the living cell, has been of much service. Ehrlich (1886) was the first to show that methylene blue stains living nervous structures. A simple way of observing this fact is given by Michaelis (1902, p. 99). A short piece of the intestine of a mouse is placed for about half an hour to one hour in a solution of methylene blue, containing one part of the dye in 20,000 of physiological saline. It is then slit open longi¬ tudinally and spread upon a slide with the serous coat uppermost. A glass cover is laid upon it with slight pressure. A little thick gum at the angles will serve to keep it in place. This prepara¬ tion can be viewed even with an immersion lens. The plexus of nerves will be distinctly seen.
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