The use of heavy metals for staining biological tissues is, of course, a standard microscope technique ; the best known application is when osmium is used. Recently, doubts have been expressed as to the correct interpretation of osmium staining (1) because of the uncertainty of the chemical reactions taking place. For a long time (2) it has been known that mercury is taken up by keratin by virtue of its reaction with sulphur from broken disulphide linkages between the polypeptide chains. This suggests that if the mercury could be detected by electron microscopy information might be obtained about the distribution of sulphur in the fibre, and if it is characteristically distributed, histological features should be made more easily evident in the microscope. The importance of investigating this reaction of mercury with keratin is emphasized by the fact that fibres containing mercury give an X-ray diffraction photograph different in certain respects from that of untreated fibres (3, 4).
Unable to display preview. Download preview PDF.