AbstractThe crosslinking of gelatin by formaldehyde in the presence of some poly‐hydroxybenzenes was studied. Model substances in which gelatin was replaced by amino acids and short peptides were prepared.The UV‐spectra of solutions of these substances show a striking resemblance to those obtained with crosslinked gelatin. From the IR‐spectra and analytical data of the model substances structural formula were deduced. The most defined structure was established for a condensation product in which the molar ratio phloroglucinol‐glycine‐formaldehyde was 1:2:6. The reactions are 1. a Mannich type, and 2. a resol type in which the link is a dimethylene ether bridge. The crosslinking reaction with gelatin seems to occur in the