Even the quack doctor, Dr. Gopalarajan, derives a real glimmer of joy from believing he has “helped, not harmed” a fellow being.
Duck calls are short, whistle-like tools used to emit “quack” sounds in order to lure ducks for hunting.
Google his name, and the top two related searches come up as “Daniel Amen scam” and “Daniel Amen quack.”
Humor and historical distance allow me to illustrate how a quack operates in a way that I could not with a contemporary example.
"I suppose you think so," replied the quack, without rancor.
If no pay is asked for the "stuff," the quack is seldom or ever a loser.
See Addison's account of some of the quack medicines of the day in Tatler, No. 224.
"You're the kind that hasn't feathers and doesn't say quack," replied Mally from below.
"That fellow is a quack," thought Miss Shirley, as she returned to Mrs. Lupton's chamber.
The Cardinal sent an intimation that he would like to see the quack.
"to make a duck sound," 1610s, earlier quake (1520s), variant of quelke (early 14c.), of echoic origin (cf. Middle Dutch quacken, Old Church Slavonic kvakati, Latin coaxare "to croak," Greek koax "the croaking of frogs," Hittite akuwakuwash "frog"). Middle English on the quakke (14c.) meant "hoarse, croaking." Related: Quacked; quacking.
"medical charlatan," 1630s, short for quacksalver (1570s), from obsolete Dutch quacksalver (modern kwakzalver), literally "hawker of salve," from Middle Dutch quacken "to brag, boast," literally "to croak" (see quack (v.)) + salf "salve," salven "to rub with ointment" (see salve (v.)). As an adjective from 1650s. The oldest attested form of the word in this sense in English is as a verb, "to play the quack" (1620s). The Dutch word also is the source of German Quacksalber, Danish kvaksalver, Swedish kvacksalvare.
duck sound, 1839, from quack (v.).
An untrained person who pretends to be a physician and dispenses medical advice and treatment.
An incompetent and fraudulent doctor
[1659+; a shortening of quacksalver, ''a person who boasts about the virtues of his worthless remedies''; fr Dutch and found by 1579]