A solid, substantially anhydrous body essentially consisting of animal or vegetal tissue and a synthetic resin substantially uniformly distributed in the tissue is prepared from a water-bearing, normally soft tissue, subject to rapid decomposition and loss of weight by evaporation of its water content in air at 20° C., by substantially completely removing the water content while substantially maintaining the original tissue shape and volume, uniformly impregnating the water-free tissue with a fluid precursor composition capable of being polymerized into a solid synthetic resin, and holding the impregnated tissue under polymerization conditions until the precursor composition is cured to a solid resin more rigid than the original tissue.