The Governor may, at any time, by a writing signed by him, direct the Comptroller to draw his order on the Treasurer, in favor of the disbursing officer of the Connecticut National Guard, organized militia or naval militia, for such sums as the Governor may find to be necessary to meet expenses for pay, subsistence and other expenses of any of said organizations or the officers or members thereof, by reason of special services ordered according to law, for the payment of which expenses no appropriation has been made or is available.