Webster’s Revised Unabridged Dictionary · 1913
Isatogen
I·sat′o·gen (ī·săt′ō·jĕn), n. [Isatin + -gen.] (Chem.) A complex nitrogenous radical, C8H4NO2, regarded as the essential residue of a series of compounds, related to isatin, which easily pass by reduction to indigo blue. — I·sat′o·gen′ic (#), a.