Registered letter or registered mail matter. When a letter or parcel sent by mail is registered
the postmaster of the postoffice where it is received makes a formal record of it and furnishes a
receipt for it to the sender and returns to the sender an acknowledgment in writing by the one to
whom it was sent of its delivery to him. Special care is taken in the transmission of the letter or
parcel/but the government will not make restitution in case of loss.