C.N. Douglas, comp. Forty Thousand Quotations: Prose and Poetical. 1917.
Monomania
Adhesion to one idea is monomania; to few, slavery.
Bovee.
The man with but one idea in his head is sure to exaggerate that to top-heaviness, and thus he loses his equilibrium.
Aaron Hill.
The greatest part of mankind labor under one delirium or another; and Don Quixote differed from the rest, not in madness, but the species of it. The covetous, the prodigal, the superstitious, the libertine, and the coffeehouse politician, are all Quixotes in their several ways.
Fielding.