Vomiting is one of the symptoms which attend a large number of ailments, and is therefore frequently encountered in general practice. To the physiologist it is of interest as an example of a complicated reflex act in which various sensory nerves and other parts of the nervous system, certain efferent motor nerves, and perhaps a definite vomiting center are concerned. The pharmacologist, who has to deal with emetics, has devoted attention to the parts of this complex mechanism on which the individual examples of this class of drugs may act. To the practitioner, however, vomiting is in general merely an indication of some disturbance, the cause of which he must discover and eliminate, if possible. There are numerous disorders, not only of a gastro-intestinal or abdominal character, but also of cerebral origin, in which the occurrence of persistent emesis is of considerable diagnostic importance.
There is a widespread assumption that