The histology section focuses on the differences in histology in the pig from other species.These differences are well documented in the literature, but many of these references are either dated or obscure.This section expands on the Necropsy chapter in Swindle and Smith, Swine in the Laboratory, Third Edition, CRC Press (2016) which was written by the author of this section by focusing on the fine histological structure of the porcine organs. The differences in porcine lymph nodes, cardiac Purkinje cells, spleen, and liver are highlighted.