When we speak of a co-operative society we usually mean a financial organization somewhat in the nature of a bank. In Europe, indeed, this is the prevailing type. The best definition of this type is ‘financial co-operative society’, since money is the binding factor or the object of such a society, either in the form of members' subscriptions, credit, or in any other form. This journal has published two articles on the problem of co-operative societies as it occurs in Africa. Both Strickland and Mumford lay particular stress upon the financial aspect of co-operation; the former suggests the regulating of the native financial position as the main task of African co-operative societies, and the latter advocates Peoples’ Banks and co-operative societies on plantations with common capital, somewhat after the manner of the Raiffeisen and Schultze-Delitzsch associations. These are but suggestions, and they can point to the complete success of this kind of co-operative society in Europe, the importance of which can also be proved from tropical lands such as India. But how do matters stand in Africa, with its peculiar conditions? Here financial co-operation has scarcely made its appearance, and it is important from the ethnological point of view to study the background which makes it difficult for financial co-operation to gain an entry. The anthropologist must ask first and foremost, whether the native knows any form of co-operative work of his own, and if so, whether this indigenous form may not be made use of to build up a system of co-operative societies which is both modern and congenial. That is the question which the practical colonial politician addresses to the anthropologist: What are the natural sources of native co-operation, and what conditions must we observe if we wish to introduce a European form of co-operation? It is obvious that if the anthropologist considers these questions, a sound principle for co-operative work among the natives can be established. Even if we ascertain that financial co-operative societies are fundamentally foreign to the native, that does not affect the necessity of introducing them to-day. We must, however, determine the difficulties which beset the introduction of a system of financial co-operation, and thus help to overcome them.