3. Master and servant, § 47*—who has burden of proving that discharge of servant was justified. The burden of showing good and sufficient grounds for discharge rests upon the employer invoking such a defense, when the servant has proved the contract, its performance up to the time of his discharge and his readiness to perform at the time of the discharge.4. Master and servant, § 48*—when prior contract of employment admissible in action for wrongful discharge. In an action for breach of contract of employment by wrongful discharge, a prior contract of employment between plaintiff and another is admissible where there is evidence that the terms of the present employment were to he determined by such contract.