At any regular or special meeting, legally called, an association organized under this Act or as a co-operative association under “The General Corporation Act”, approved June 28, 1919, as amended may, by a majority vote of its members invest not to exceed twenty-five per cent of its paid-up common stock and reserve fund in the capital stock of any corporation or other co-operative association; and any association organized under this Act or organized as a co-operative association under the General Incorporation Act, which is a member of, and is selling its products to or through or buying products from or through another association organized under this Act, or as a co-operative association under the General Incorporation Act, may hold stock in such latter association to any amount which is necessary in order that continuous capital may be raised for such latter association from its member associations, based in amount upon the volume of business transacted by such member associations with said association: Provided, however, that ten days’ notice has been previously given to each shareholder, stating in said notice the purpose of the meeting.