The corporation shall be deemed an institution for savings, and together with all accumulations therein shall not be taxable under any law which shall exempt building and loan associations or institutions for savings from taxation; nor shall any law passed taxing corporations in any form, or the shares thereof, or the accumulations therein, be deemed to include corporations doing business in pursuance of the provisions of this Article, unless they are specifically named in such law. The shares of credit unions, being hereby regarded as a system for saving, shall not be subject to any stock-transfer tax either when issued by the corporation or transferred from one member to another. (1915, c. 115, s. 26; C.S., s. 5225; 1925, c. 73, ss. 3, 16; 1935, c. 87; 1975, c. 538, s. 1.)