Development center distribution and form of developed silver produced by lith and ordinary development of lith emulsions with and without polyethylene oxides (PEO) are observed by electron microscope. PEO has no influence on ordinary development of the emulsions. In lith development of the emulsion containing PEO, a fairly long induction period is observed which terminated by explosive development. After lith development, silver specks of about 1000Å in diameter are recognized even in the region of optical density equal to zero. It can therefore be presumed that oxidation of latent images is not occured in such a region.