This chapter shall not apply to the sale of farm products at public auction by an auctioneer acting as the agent of another to whom such farm products shall have been consigned, nor to farm products purchased outright and unconditionally or for cash f.o.b. at point of origin, nor to dealers who buy farm products solely through solicitation by means of circulars or price lists, stating plainly on the face of such literature that they are not commission merchants and do not make a charge against shippers for selling or handling such products and who do not in any fashion solicit farm products on consignment to sell for the account of the shipper.