A garnishment execution may be made returnable at any time not less than ten (10) but not more than ninety (90) days after its receipt by the sheriff, to the clerk with whom the judgment roll is filed. When the execution is returned, the clerk must attach it to the judgment roll and record the execution and the return thereto at large, and certify the same under his hand as true copies in a book to be called the "execution book," which book must be indexed with the names of the judgment creditors and judgment debtors in execution alphabetically arranged, and kept open at all times during office hours for the inspection of the public without charge. It is evidence of the contents of the originals whenever they, or any part thereof, may be destroyed, mutilated or lost.