In situ hybridization for IgJ in the gravid d13.5, d16.5, d18.0 and d19.0 wild-type and Cox-1 KO mouse uteri. In situ hybridization was performed (n = 4) from each gravid time point and non-gravid mice (n = 2). Shown are representative light-field images (left) and dark-field images (right) (25×). The slides were counterstained with hematoxylin and eosin. Areas of hybridization appear white, demonstrating deposition of silver granules.