I. HISTORICAL BACKGROUND OF THE PROBLEM
The human salivary glands are among the most complex of all the glands of the body. They are relatively poorly understood, and many controversial issues have sprung up about their mechanisms, secretions and functions. The many inconsistencies in data in the literature are probably due in great part to the differences in technic which were used for the collection and study of their secretions. This is particularly true of the parotid glands. Therefore, the history of knowledge of the secretory reactions of the human parotid glands resolves itself to a large extent into a story of methodologic changes.From 1832, when Mitscherlich1 reported his first observations on human parotid secretion, till 1916 there were two methods used for the collection of isolated salivary secretions. These were direct collections from fistulas and collection by the use of cannulation. Six physicians who had patients with