The prescription of "bitters" of various sorts belongs to those inherited procedures in practical medicine that antedate the modern period of scientific criticism and therapeutic skepticism. Why they are ordered, or what they really accomplish for the person who takes them, has usually either been answered in only the vaguest terms, or overlooked entirely by teachers of therapeutics. As a rule, these "bitters" are believed to stimulate the appetite. Bitters have even been grouped into classes, such as "pure bitters," of which calumba is an example; astringent bitters, to which the decoction of cinchona belongs, and aromatic bitters, including cascarilla or orange. Persons who eat too much and exercise too little were at one time wont to take "sherry and bitters" before dinner "to stimulate the appetite."
So far as the reputed action of bitters is subjective, producing an impression due to suggestion on the individual rather than to any