27. Every person capable of binding himself or of being bound, by the making, drawing, acceptance or negotiation of a negotiable instrument, may so bind himself or be bound by a duly authorised agent acting in his name. A general authority to transact business and to receive and discharge debts does not confer upon an agent the power of accepting or indorsing bills of exchange so as to bind his principal. An authority to draw bills of exchange does not of itself import an authority to indorse.