We employ a somewhat similar expression, when we say, "both of the same kidney."
C. I. R.
This expression may be traced beyond "the scholastic doctors and casuists of the middle ages." Erasmus, in his Adagia, says,—
"Ejusdem farinæ dicuntur, inter quos est indiscreta similitudo. Quod enim aqua ad aquam collata, idem ad farinam farinæ. Persius in 5 Satyr.
"'Nostræ paulò antè farinæ,
Pelliculam veterem retines.'"
And again, on the proverb "Omnia idem pulvis," he says,—
"Quin nobis omnia idem, quod aiunt, pulvis: alludens ad defunctorum cineres, inter quos nibil apparet discriminis. Confine illi quod alio demonstravimus proverbio, ejusdem farinæ. Siquidem antiqui farinam pollinem vocabant."
Is. Casaubon, in a note on the above passage of Persius, says,—
"Proverbium Latinum ad notandum similitudinem, 'est ejusdem farinæ,' proprie locum habet in panibus."