. . . . . . . "No person, firm, or corporation, or any agent thereof, other than a national bank or a bank or trust company duly incorporated under the laws of this state, or a pawnbroker, as provided in chapter 235 of the Public Acts of 1905, shall, directly or indirectly, loan money to any person, and directly or indirectly charge, demand, accept, or make an agreement to receive therefor interest at a greater" .