Saliva
2 of the 7 encyclopedias on this shelf carry an entry for Saliva. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
the fluid of the mouth, sometimes called spittle. In man there are three salivary glands on each side of the head. They discharge their contents through ducts into the mouth during the process of chewing. The largest, from two to three inches in length, lies in front of the ear and discharges its saliva into the mouth just above the second upper premolar tooth. Saliva moistens dry food so as to render the process of swallowing easy. It also begins the process of digestion. After a moment of chewing, a mouthful of dry bread acquires a slightly sweetish taste. This is due to the action of saliva which changes some of the starch into sugar, one of the first steps in digestion. For this reason physicians recommend that food be chewed well. Most mammals have salivary glands, but they are absent in the whale. Most reptiles, except the crocodile, are furnished with saliva, with which they cover their food copiously before swallowing. It is entirely wanting in the fishes. The sticky substance which causes insects to adhere to the wood-pecker's tongue is a kind of saliva. The chimney swift builds its nest largely of saliva. The edible birds' nests of the Chinese are made of this material. An ox fed on hay and other dry food secretes about 112 pounds of saliva daily. A horse requires about 92 pounds. Sallust (86-34 B. C.), a Roman historian in the time of Caesar. Sallust was a member of the Senate and held a number of important positions under Caesar. As proconsul, he accumulated a large fortune in Africa. At Caesar's death, he retired to private life in a beautiful villa and devoted himself to historical study. Sallust appears to have written a history of some pretension, taking Thucydides for his literary model, but, save a few fragments, the work has been lost. Two short histories, The Jugurtha and Catiline's Conspiracy, are his present claim to notice. In point of time he preceded Livy and, in fact, all other Roman historians save Caesar. See Catiline
Collier's New Encyclopedia (1921)
the transparent watery fluid secreted by glands connected with the mouth. The quantity secreted in 24 hours varies; its average amount is probably from 1 to 3 ounces . The purposes served by saliva are mechanical and chemical. It keeps the mouth in a due condition of moisture, and by mixing with the food during mastication it makes it a soft pulpy mass such as may be easily swallowed. The chemical action of saliva on the food is to convert the starchy elements into some kind of sugar. The salivary glands are compound tubular glands known as the parotid, the sub-maxillary, and the sub-lingual, and numerous smaller bodies of similar structure, and with separate ducts , which are scattered thickly beneath the mucous membrane of the lips, cheeks, soft palate, and root of the tongue. Salivary glands are absent in some mammals and reptiles, and in most fishes. exciting or producing an unusual secre- SALIVATION , the act or process of tion and discharge of saliva, generally by the use of mercury ; ptyalism; an abnormally abundant secretion and flow of saliva. order SalicaceÓ•.