"Se non è puro il vase, ecco già guasto
Che che v' infondi."
And by Francis (vol. iv. p. 27., 6th edit.):—
"For tainted vessels sour what they contain."
The context shows that this is the correct translation, as sincerum vas is obviously in opposition to "auriculas collectâ sorde dolentes," in the preceding line.
The line itself plainly refers to the well-known fact, that if wine or other liquor be poured into a foul vessel, it will be polluted by it. Nor can I avoid noticing the elegant opposition, according to this construction, between the sweetness in sincerum, and the acidity in acescit.
I also think that Mr. Inglesby's version cannot be correct for the following reason. Cracks may exist in every part of a vessel alike; and as the part filled by the liquor is always many times greater than the remainder of the vessel, cracks would more frequently occur in the former; and, as where air can get in the liquor can get out, it
is plain that in the majority of instances the liquor would run away instead of turning sour. Now the line plainly contains a general affirmative proposition that all liquor whatsoever will be turned sour, unless the vessel be sincerum; and therefore that version cannot be right which applies only to a few instances.
"Sincerum cupimus vas incrustare" is well rendered by Gargallo (vol. ii. p. 37.):
" . . . . Insudiciar bramiamo