I'KOJECTION MICROSCOPY 



used in light and electron microscopy and 

 x-ray medical diagnostic. For example, I2 or 

 Li-KI solutions will stain cellulose, and OSO4 

 will stain unsaturated fatty acids (see Fig. 

 10). BaS04-sugar mixture can he fed to small 

 insects (19). Shadowcasting with a heavy 

 metal will reveal surface structure (see Fig. 

 5 and Fig. 11). Replicating allows study of 

 the coarse surface of thick heavily absorbing 

 specimens. For relatively thick specimens 

 such as fabric, (Fig. 12), w^ood particles (Fig. 

 13), small insects (Figs. 14, 15) etc., an anode 

 voltage of 10-12 kV can successfully be used. 

 The technique of selective staining, like 

 fat particles by OSO4 , is still in its initial 

 stage. Using different staining agents and 

 radiating with x-rays of different wave- 

 lengths may show' the distribution of the 

 concentration of some chemical compounds 

 in the specimen. The different pictures ob- 

 tained in this way may be superimposed 

 after suitable coloring, and thus a color pic- 

 ture can be obtained. 



Fig. U. Tissue paper, gold shadowed, ca 63X. 

 (Experimental Delft microscope.) 



Fig. 10. A section of mouse skin, stained with 

 OSO4 . (Experimental Delft microscope.) 



Fig. 12. Nylon stocking. (T.P.D. microscope.) 



Stereomicroscopy 



As a result of the large depth of field, it is 

 often very difficult to get an idea of the 



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