Journal Archive

Platinum Metals Rev., 1970, 14, (4), 139

Platinum Metal Coatings for Stereoscan Specimens

The Stereoscan electron microprobe system produced by Cambridge Instruments Limited eliminates much time-consuming specimen preparation work associated with, for example, transmission electron microscopy. Specimen preparation generally involves only drying, fixing on to the specimen stub and rendering the specimen conductive by evaporating a metal layer, e.g. 300 to 500 Å gold-palladium alloy, on to it to prevent charge formation without masking the surface detail and impairing resolution.

Workers at the London School of Hygiene and Tropical Medicine, under the direction of Professor A. W. Woodruff, have now used rhodium vapour in this way to obtain excellent Stereoscan pictures of the surface of Toxocara canis larvae, which occur in the intestines of dogs. Larvae which arise in man from the eggs of Toxocara canis burrow into the human intestine wall and are carried by the bloodstream to organs such as the eye, where damage may occur. They also predispose man to virus infections such as poliomyelitis.

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