Nearly every form of letter that has been devised for collecting physicians accounts has been based upon those used by installment houses and those in general use by wholesale merchants who deal with retail dealers. They all carry the bluff idea. This is all right in dealing with installment customers with whom you have a contract that will take away the goods purchased, or with retail merchants who know they must meet their obligations if they continue in business. The credit men of mercantile institutions keep tab on their customers through the local merchants exchange and the commercial agencies, and are in a position to know to what extent it is safe to extend credit. The merchant cannot refuse to pay his bills and go to another wholesale house and buy goods, hence if he is a little tardy in meeting his obligations the bluff letter will awaken him to the necessity of paying the bill. With the doctor's customers it is altogether different. He knows that he cannot be compelled to pay the bill, and that some other physician will be only too ready to come at his call. It is then evident that the bluff idea will not work with the man who knows that he can get another doctor whenever he wants one, and that he is so protected by the exemption laws that the bill cannot be collected by resorting to law. So in reaching this class we must devise other plans if we hope to accomplish anything. Here, my experience has shown that sentiment is the key note in an effective collecting letter for physicians. I have found that the more human interest, sentiment and friendly feeling that can be woven into the letter the better it is. Every time that I write a letter to a client I try and refer in some manner to the patient or to some member of the family, and try to impress them with the fact that I have a personal interest in them. The following forms are suggestive of the idea, and have proven very successful in my practice. The classification is, of course used with every account--they are all No. 1 until they fail to pay. The word "Class" and the number are stamped with a rubber stamp. Letters of this kind should be pen written--typewriter and form letters will not answer, they lose the personal sentiment. A duplicator that will easily reproduce 100 copies of a pen written letter may be had for about $5, and the letters may be "formed" on this, leaving space in which the personal matter may be written. If properly done they will have the appearance of a hand written letter. Don't have your letters too polished. Remember you are a very busy man--just writing a note to a friend. Omit the rhetorical embellishments from this class of correspondence in all cases. The first of my series of letters is along the following line. CLASS 1. Dear Sir:--