Section 91. Cities having one hundred thousand or more inhabitants as determined by the last national census, and cities and towns having less than one hundred thousand inhabitants as determined as aforesaid and already possessing and continuing to furnish satisfactory tuberculosis hospital provision, shall be exempt from the provisions of sections seventy-eight to ninety, inclusive; provided, that no city included within a tuberculosis hospital district shall become entitled to such exemption by reason of any change in the number of inhabitants of such city, and provided, further, that each city or town of less than one hundred thousand inhabitants as aforesaid, which on July first, nineteen hundred and twenty-seven or at any time thereafter shall have failed to furnish tuberculosis hospital provision to the satisfaction of the department in a tuberculosis hospital maintained by said city or town or in a building or ward of a hospital set apart by it for its tubercular patients, or in any other public or private facility caring for patients with tuberculosis, shall, upon receipt of written notification from the department of such failure, become and be a part of the district of the tuberculosis hospital for the county or section thereof in which such city or town is situated; and provided, further, that any city or town may, at any time upon application and payment of its proportionate share of the actual construction costs, as hereinafter provided, of said county tuberculosis hospital, if any, become a part of the hospital district of the county or section thereof in which it is situated. Each city or town becoming, by reason of its failure to comply with this section or upon application as aforesaid, a part of a county hospital district shall pay to the district treasurer its proportionate share of the actual construction costs of said county tuberculosis hospital, if any, including land, buildings and equipment, computed as of the date of such failure or such application. In case the city council of such city or the selectmen of such town and the trustees of such county tuberculosis hospital do not agree on the amount of such proportionate share within three months after the receipt by said city or town of written notification from the department of failure as aforesaid or within three months after application as aforesaid, the amount of such share shall be determined by a valuation board consisting of the mayor of the city or the chairman of the board of selectmen of the town, a person to be selected forthwith after the expiration of said three months' period by the county commissioners of the county in which such city or town is situated, and a third person to be selected by the other two. If the representatives of the city or town and the county do not, within thirty days after the selection of the county representative on said board, agree upon a third member thereof, such third member shall, on petition therefor by any party in interest to the supreme judicial court, be appointed by a justice thereof. The decision of a majority of said valuation board shall be final.

Any city or town, not excepting those in excess of one hundred thousand population, which, on June first, nineteen hundred and fifty-four, was meeting the provisions of this section and section ninety-two for the care of tuberculosis patients in a hospital maintained by the city or town, may by contract, with the approval of the department, provide for such hospital care with any other city or town or with any county or with the department or with a private charitable tuberculosis sanatorium or hospital as provided in section seventy-nine, and any such city or town contracting for such care shall be exempt from the payment of construction costs of existing county sanatoria.