Paul Ponder, Noctes Atticae, or Reveries in a Garret; Containing Short, and Chiefly Original, Observations on Men and Books
(Bath: Richard Cruttwell, 1825), p. 68:
The introduction of parentheses into any form of composition is both improper and unscholarlike; for it is a proof that the writer is not conversant with the art of good writing, or that he writes in a hurry. Unlettered men, and those who are accustomed to speak with little thinking and with much haste, fall into this error. The nominative case, the verb, and its government, will always make a plain and intelligible sentence, and admits of such infinite changes that there seems no necessity for these entanglements of speech. My Lord Clarendon's History is full of them; and they render his composition, with all the good and grand sense of the author, embarrassing. A man before he pretends to be a writer should be a grammarian, and not subject himself, by an obscure or harsh style, to the old sarcasm, "Nomine grammaticus re barbarus."
Related post: Footnotes and Parentheses