We may look first at the early, primitive type of heterogeneous banking institution in which there was practically little or no limitation of function. The banks of the early modern period in Europe were of this variety. They loaned upon real estate, took personal property in pledge, issued notes, accepted foreign coin or bullion and held it on deposit, eventually issuing credits which took the form of deposit accounts, and also did more or less of a real-estate and mortgage business. As time went on it was seen that good banking called for a differentiation of function, and that the best results were obtained either by departmentalizing banks and keeping their various activities separate one from another, or else by creating different kinds of institutions, each of which was qualified to perform a special function or duty. Thus in British banking a sharp distinction came to be drawn at an early date between the commercial bank which dealt only in very short-term five paper, and the institution which undertook corporate financing, promoting companies, and the making of investments. In the United States this distinction was carried still farther, and as our trust companies grew up they assumed fiduciary functions, acting as trustee, receiver, guardian, and in many other capacities. They were often essentially investment institutions dealing in long-term securities, bonds, mortgages, and the like. Differentiated from these trust companies, were the savings banks, whose duty it was to gather small funds from a great number of persons and to invest them in safe securities of some kind which as the result of custom came to be chiefly real-estate mortgages in various forms. The commercial banks, on the other hand, fell into one or two broad classes according as they served primarily agricultural or manufacturing interests. In general it may be said that the progress of banking development tended, either as a result of legislation or of practice, to differentiation of banking operations either on the basis of security taken, or of period for which loans were made, or of the form of loan, whether in the form of an actual advance of money or of the issue of notes, or the establishment of deposit accounts. Looking over the world to-day, there may be seen in the less developed countries many banks which still exercise a great variety of functions, and even in some of the more advanced commercial countries, as in the United States, it is to be observed that the banks in the more primitive communities perform a greater diversity of functions than are customarily undertaken by the larger banks.