VOMITING

like swallowing, is a muscular act controlled by the nervous system. The nerve centre which controls this act, situated in the medulla oblong at a, is termed the “vomiting centre” (see Brain). The act is not under the control of the will, but is produced whenever the vomiting centre is irritated. The various causes of irritation may be cla ified thus:— a ae a on the vomiting centre, e.g.; ax acmeen th the tire alation of the brain, os is migraine, concu ion, esa 8 tumour on the braia, and (2), the supply of impure bi to the brain as in fever, Bright’s disease and many poisons, “O Causes acting indirecly on the ee J centre from Seinen cee Sue ee mrerreat unpleasan and am; Qy irritation of the nerves of tho throat, stomach, and other viscera, as in tickling the throat with a feather, 2 F [s. 422]