Mistrust first impulses, they are nearly always good.
Défiez-vous des premiers mouvements, ils sont presque toujours bons.
Original text (French)
Source, in full
Quoted by Rees Howell Gronow in Reminiscences of Captain Gronow, formerly of the Grenadier Guards and M.P. for Stafford, being Anecdotes of the Camp, the Court, and the Clubs, at the close of the last War with France (1862)