PHOTOMICROGRAPHY 191 



screws for correct alignment. Unless the equipment can be permanently- 

 aligned, it should be aligned immediately before taking a picture. 

 Especial care must be taken with long-focus condensers (see Section 3.1 

 of Chapter IV). 



Otherwise photomicrography with the phase microscope is the same 

 as with other equipment, and the standard books on photography 

 should be consulted (Jackson, 1948; Anon., 19*4-4; Shillaber, 19-44). 



