Whenever, in the judgment of the municipal board or body having charge of the finances in any city of the first class, the buildings and property devoted to the use of a city hospital shall be deemed to be insanitary, improper or inadequate, such board or body may issue bonds, either registered or coupon, to an amount not exceeding three hundred thousand dollars, and to sell the same, at public or private sale, to raise money to pay for the erection and construction and furnishing of a new hospital building or buildings in place of the hospital building or buildings determined as aforesaid to be insanitary, improper and inadequate, and to purchase lands necessary for the same. All moneys received from the sale of such bonds shall be applied and used for the purposes herein enumerated, and for no other purpose.