Section 21. Any unissued capital stock from time to time authorized under the articles of organization may be issued by vote of the stockholders, or by vote of the directors under authority of a provision of the by-laws or a vote of the stockholders, which provision or vote may be adopted before or after the stock is authorized. No stock shall be issued unless the cash, so far as due, or the property, services or expenses for which it was authorized to be issued, has been actually received or incurred by, or conveyed or rendered to, the corporation, or is in its possession as surplus.