E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Evil Communications,
etc. He who touches pitch must expect to be defiled. A rotten apple will injure its companions. One scabby sheep will infect a whole flock.
1
French: Il ne faut qu’une brébis galeuse pour gâter tout un troupeau.
2
Latin: Mala vicini pecoris contagia lædent (Virgil). Tunc tua res agitur, paries cum proximus ardet. Mala consortio bonos mores inquinat. Malorum commercio reddimur deteriores. Hic niger est, hunc tu, Romane, caveto (Horace). Uva conspecta livorem ducit ab uva.
3
To the same effect is the locution, “C’est une brébis galeuse,” and the idea implied is, he must be separated from the flock, or else he will contaminate others.
