"Idiosyncracies" is a medical journal by Sir Humphry Rollestone, who served as physician to King George V of the United Kingdom. Sir Rollestone looks at the medical condition of 'Idiosyncracies' defined variously as, "(1) a physical constitution peculiar to an individual, now only in medical use, (2) the mental constitution peculiar to a person or class of persons; a view or feeling, a liking or aversion, and (3) a mode of expression peculiar to an author." He posits that the abnormal reactions of idiosyncracy may be either on the one hand greatly exaggerated or on the other hand greatly diminished; more briefly it may be described as an unusual physiological personal equation. The various manifestations of the condition give rise to the chapters of the book: psychological ideosyncracies, physiological ideosyncracies, Food ideosyncracies, Drug ideosyncracies, as well as conditions such as Hay Fever, Asthma and other allergenic diseases that are a subset of the condition.