5'-nucleotidase (5'-Nase)-dipeptidyl aminopeptidase IV (DAPase)-alkali
ne phosphatase (ALPase) triple staining was used to differentiate lymp
hatics from venous and arterial capillaries in a variety of mammalian
tissue sections including human. This triple staining method facilitat
es specific identification under a Eight microscope of 5'-Nase activit
y in lymphatics, DAPase activity in venous capillaries and venules and
ALPase activity in arterial capillaries and arterioles. This techniqu
e depicts initial lymphatics more clearly and extensively than other m
ethods so far reported although some interspecies and tissue differenc
es are obtained in each enzyme activity.