☞ In man the saliva is a more or less turbid and slighty viscid fluid, generally of an alkaline reaction, and is secreted by the parotid, submaxillary, and sublingual glands. In the mouth the saliva is mixed with the secretion from the buccal glands. The secretions from the individual salivary glands have their own special characteristics, and these are not the same in all animals. In man and many animals mixed saliva, i.e., saliva composed of the secretions of all three of the salivary glands, is an important digestive fluid on account of the presence of the peculiar enzyme, ptyalin.