T r a v n i k P., D. H 0 r k y: A Technique for the Oemons.tration of Immunoglobulins in the Cumulus oophorus-Oocyte Complex of the Pig. Acta vet. Brno, 56, 1987: 487-493. An optimized procedure for the demonstration of immunoglobu lins in the pig cumulus oophorus-oocyte complex in semi-thin sections is described. Non-specific porcine immunoglobulIns of class G were demonstrated by means of peroxidase~label led goat antiserum, and specific immunoglobulins of class G against Aujeszky's disease virus were demonstrated using the correspond ing antigen and peroxidase-labelled porcine antibodies against this antigen. A most convenient mode of removing the embedding medium was developed, the composition of the incubation solution for the demonstration of peroxidase activity was improved and a number of checks on th~ specificity of the reaction were tested. The procedure proved most useful for the demonstration of specific and non-specific immunoglobulins both in docytes and in the cu mulus oophorus. Oocyte, cumulus oophorus, immunoglobulins, immunocytochemistry, semi-thin sections. Light microscopic examination of semi-thin sections provides sufficient information on the location of a substance as to whet her it is present in the cumulus·oophorus cells, intercellular spaces of the cumulus, in the zona pellucida, perivitelline space, cytoplasm or in the nucleus of the oocyte. Moreover, semi-thin sections of the cumulus-oocyte complex are easier to prepare than traditional paraffin-embedded sections. In the light of these considerations we chose the immunocytochemical demonstration of specific and non-specific immunoglobulins in semi-thin sections