Same; investment of reserve fund. At any regular meeting, or any duly called special meeting, at which the quorum fixed by the bylaws shall be present, the shareholders of any cooperative corporation may by a majority vote of such shareholders present in person, subscribe for shares and invest a portion of the reserve fund of such corporation, not to exceed at any time 20 per cent in the aggregate of its capital, in the capital stock or membership capital of any other cooperative corporation or corporations with which it desires to cooperate or affiliate: Provided, however, That this provision shall not be construed to prevent such corporation from accepting patronage dividends in the form of stock or otherwise from such other corporation in any amount.