The directors or other officers of such a company making or authorizing an investment or loan in violation of sections sixty-three, sixty-five or sixty-six shall be personally liable to the stockholders for any loss caused thereby.
If they allow to be insured on a single risk a larger amount than authorized by section twenty-one, they shall be personally liable for any loss in excess of the amount to which they might lawfully insure.
If they make or assent to further insurance knowing that the accrued losses of the company equal its net assets, they shall be personally liable for any loss under such insurance.