Abstract
1. Indophenol blue synthesis has been studied in fresh frozen sections and formalin-treated fresh frozen sections of the major rat salivary glands.
2. In fresh frozen sections ("G" Nadi reaction), indophenol-blue synthesis was consistently more rapid and more intense in ducts and tubules than in acini.
3. 10% formalin treatment of fresh frozen sections completely abolished indophenol blue synthesis by duct and tubule structures in all glands. However, after approximately one hour of incubation of these treated sections, indophenol blue appeared ("M" Nadi reaction) in the acini of submaxillary and parotid glands, but not in the acini of the sublingual gland.