§58. Deductions from gross income; bad debts
In computing net income, deductions shall be allowed for debts which become worthless within the taxable year, or, in the discretion of the collector, for a reasonable addition to a reserve for bad debts; and when satisfied that a debt is recoverable only in part, the collector may allow such debt as a deduction in an amount not in excess of the amount charged off within the taxable year.