79. Agent's ordinary duty to use care and skill.

Every agent1, including a gratuitous agent2, is responsible to his principal for any loss occasioned by his want of proper care, skill or diligence, in the carrying out of his undertaking3, even though the principal has himself been negligent in not discovering the agent's breach of duty4. No absolute standard can be laid down as to what constitutes proper care, skill or diligence, and each particular case must be judged by its own circumstances