An entire contract is one the consideration of which is entire on both sides. The entire fulfillment of the promise by either is a condition precedent to the fulfillment of any part of the promise by the other. Whenever, therefore, there is a contract to pay the gross sum for a certain and definite consideration, the contract is entire. A severable contract is one the consideration of which is, by its terms, susceptible of apportionment on either side, so as to correspond to the unascertained consideration on the other side, as a contract to pay a person the worth of his services so long as he will do certain work; or to give a certain price for every bushel of so much corn as corresponds to a sample. Potter v. Potter, 43 Or. 149, 72 Pac. 702; Telephone Co. v. Root (Pa.) 4 Atl. 829; Horseman v. Horseman, 43 Or. 83, 72 Pac. <198; Norrington v. Wright (C. C.) 5 Fed. 771; Dowlev v. Schiller (Com. PI.) 13 N. Y. Supp. r>r>2: Osgood v. Bander, 75 Iowa, 550, 39 N. W. S87, 1 L. R. A. 055. Where a contract consists of many parts, which may be considered^ as parts of one whole, the contract is entire. When the parts may be considered as so many distinct contracts, entered into at one time, and expressed in the same instrument, but not thereby made one contract, the contract is a separable contract. But. if the consideration of the contract is single and entire, the contract must be held to be entire, although the subject of the contract may consist of several distinct and wholly independent items. 2 Tars. Cont. 517.