The sending of any letter or communication through the mail which is "calculated by the terms or manner of display and obviously intended to reflect injuriously upon the character of another, is an offense." Under this statute, a collection agency by sending a paper through the mails containing notices of accounts against persons who fail to pay their debts and advertising such accounts in the paper commits a criminal offense, such publications appearing to have been made for the purpose of coercing payment.34 So the sending of a postal card through the mail making demand on a person to pay a debt, with the threat that if not paid at once the claim will be placed in the hands of a lawyer, is an offense.35 But the sending of a respectful dunning letter in an unsealed envelope, with the name of the collection agency thereon, such as Mercantile Protection and Collection Bureau, is not a violation of the law forbidding the sending of envelopes bearing any language of a defamatory or threatening character.36