"particular happiness"...............

Benjamin Rush,  Charles Willson Peale, 1783.

     But Benjamin Rush made quite a first impression.  He was tall, lean, and handsome with active blue-grey eyes and an aquiline nose.  His long blond-brown hair, tied back in a loose ponytail, accentuated his most prominent feature:  an uncommonly large head.  To some, the size of his skull bespoke "strength and activity of intellect." while others viewed him as having a head overfull of ideas he couldn't keep to himself.
      Unlike the pedigreed doctors who had trained him in America, Scotland, England, and France, Dr. Rush was a medical and political prodigy from a middle-class family on the humbler side of Philadelphia.  He had lost his father, a gunsmith, at the age of five, leaving him and his five siblings to be raised by their mother, who opened a package good store and tavern just down the street from Benjamin Franklin's print shop and post office.  But because of young Rush's astonishing mind - besides total recall, he had what he referred to as the "particular happiness' of being able to synthesize and humanize disparate ideas into searing rhetoric - he had finished school at thirteen, graduated from the College of New Jersey (now known as Princeton) at fourteen, finished medical training in Edinburgh and London at twenty-two, and began practicing and teaching medicine at twenty-three.  He was still single in his late twenties because his family had convinced him it would be bad for his career to marry before thirty.

-Stephen Fried,  Rush:  Revolution, Madness & The Visionary Doctor Who Became A Founding Father