Measles
2 of the 7 encyclopedias on this shelf carry an entry for Measles. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
an infectious disease, called also rubeola, most frequently attacking children, though sometimes occurring in old age, as in the case of George III. and of Otho, ex-King of Greece, who died of this affection. The period of incubation is about eight days, when the rash appears, accompanied by catarrh, watery eyes, acrid watery discharge from the nose, sneezing, and often pain in the forehead, y ead, with, occasionally, bleeding at the nose. The bronchi are frequently affected, this forming the chief danger. The spots are small red, papular, and crescent-shaped, commencing on the face and passing downward, disappearing in the same order. The old-fashioned remedy is saffron-tea, but the chief neces sity is to ward off any respiratory mischief, or to combat it when present. A form of measles known as rötheln, or German measles, is distinct from measles, or from scarlatina, with which it has often been confounded. The eruption lasts longer, never less than four or five days, sometimes 8 or 10, and differs slightly from that of measles or scarlatina. It is usually a very mild disease, requiring only an aperient saline, with liquid food, and keeping in bed for a few days.
Aiton's Encyclopedia (1910)
me'z'lz, a contagious disease characterized by mottled eruptions of the skin. It is thought to be a disease of considerable antiquity. Though with proper care it is not dangerous, it is very annoying. One who has had the disease is not likely to take it again. Medical science has not yet determined the specific cause, but it is thought to be due to a bacterium. In any case, the measles are communicated through the atmosphere by means of clothing, etc. From seven to fourteen days usually pass between the time of exposure and breaking out. Four thousand three hundred and two deaths from measles were reported from certain areas in the United States for the year 1907, a slight increase over the rate reported in the previous census. Singularly enough, the soldiers of the Confederate army were subject to an epidemic of the measles from which many died. See Disease