Enzyme triple staining for differentiation of lymphatics from venous and arterial capillaries

5'-nucleotidase (5'-Nase)-dipeptidyl aminopeptidase IV (DAPase)-alkaline phosphatase (ALPase) triple staining was used to differentiate lymphatics from venous and arterial capillaries in a variety of mammalian tissue sections including human. This triple staining method facilitates specific identification under a light microscope of 5'-Nase activity in lymphatics, DAPase activity in venous capillaries and venules and ALPase activity in arterial capillaries and arterioles. This technique depicts initial lymphatics more clearly and extensively than other methods so far reported although some interspecies and tissue differences are obtained in each enzyme activity.