- The condition, quality, or relation of metameric
substances, or their respective derivatives, which are more or less
interchangeable, according as one form or the other is the more stable.
It is a special case of metamerism; thus, the lactam and the lactim
compounds exhibit tautomerism.
- Any one of a series of nitrogenous bases, resembling the
amines and produced by the reduction of certain nitroso and diazo
compounds; as, methyl hydrazine, phenyl hydrazine, etc. They are
derivatives of hydrazine proper, H2N.NH2, which is a doubled amido
group, recently (1887) isolated as a stable, colorless gas, with a
peculiar, irritating odor. As a base it forms distinct salts. Called
also diamide, amidogen, (or more properly diamidogen), etc.