of approximately 60 nm. The ribbons of sections are floated onto the surface of water
and their interference colours are used to assess their thickness. The desired 60 nm
section thickness has a silver/gold interference colour on the water surface. The
sections are then mounted onto copper or goldEM grids, and are subsequently stained
with heavy metals, for example uranyl acetate and lead citrate.(a) (b)
(c)Fig. 4.21Transmission electron microscopy (TEM). (a) and (c) Ultrathin Epon sections (60 nm thick) of developing
rat sperm cells stained with uranyl acetate and lead citrate. (b) Carbon surface replica of a mouse sperm preparation.131 4.6 The electron microscope (EM)