from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
COMMON COUNTS. Certain general counts, not founded on any special contract,
which are introduced in a declaration, for the purpose of preventing a
defeat of a just right by the accidental variance of the evidence. These are
in an action of assumpsit; counts founded on express or implied promises to
pay money in consideration of a precedent debt, and are of four
descriptions: 1. The indebitatus assumpsit; 2. The quantum meruit; 3. The
quantum valebant; and, 4. The account stated.