Nevertheless, there are some principles which stand out so clearly in this kind of cost analysis as to make it possible to limit costs quite definitely. For instance, assuming that every loan is made only after a careful credit analysis of the concern which applies for it, it is clear that very much the same amount of investigation must be made in order to lend with entire safety $10,000 to a concern that would have to be made if the loan were $25,000. In the same way it evidently costs about as much for a bank to pay a check of $100 as it does to pay a check of $1. The banker can, therefore, to some extent limit himself by prescribing the size of the transactions which he will undertake. He may make what amounts to a fixed rule that no loans shall be made under ordinary circumstances below a given amount, or that he does not expect his customers to draw checks below a certain amount. More important still, he may inform his customers that they must keep on deposit with him a minimum balance in an amount whose interest is estimated to about carry the cost of their business transactions. In all of these ways he may seek to cut down an excessive volume of transactions and thereby to reduce the expenses connected with them, especially in those cases where the volume of business is in very small units and represents a kind of transaction that is unproductive or unre-munerative. Having fixed these broad general limitations upon his business, the banker can, thereafter, guard himself only by careful and constant analysis of each account in order to make sure whether it is profitable or not. In so doing he ascertains the amount of the various kinds of work which he has to do in keeping the account going - the number of checks paid and the various other items of accommodation asked for by the customer. Particularly does he seek to assure himself that the account is a five one - that is to say, that it consists of funds which are actually in hand and not funds that are merely in process of being collected or likely to come in at some time in the future. If the account is merely a nominal sum composed of collection items against which the customer is constantly drawing, the banker may be safe enough, but he is simply supplying his customer with money. In such a case the banker's protection is merely that of requiring his customer not to draw against any balance that has not been actually collected.