Any burial lot in any cemetery controlled by any company or association incorporated for cemetery purposes under any general or special law of the State of Illinois, may, by the owner or owners, be conveyed or bequeathed back to and held by such company or association in perpetual trust for the purpose of its preservation as a place of burial, and shall thereafter remain forever inalienable by act of the parties, but the right to use the same as a place of burial of the dead of the family of the owner and his descendants shall descend from generation to generation unless the deed of conveyance in trust shall provide that interments in such lot shall be confined to the bodies of specified persons, in which case such lot shall be forever preserved as the burial place of the persons specified in the deed and shall never be used for any other purpose whatever. However, in all cases where in addition to the cemetery corporation there is a special corporation or board of trustees created for the purpose of taking and preserving an improvement fund or funds for the respective cemetery, then and in such instances conveyances in trust of burial lots to be held in perpetuity may be made to and held by such special corporation or board of trustees, upon the same trust, provisions and conditions as are above provided in case of conveyances to cemetery companies. However, no conveyance in trust authorized by this Act shall be made without the consent of the cemetery company or association in whose cemetery such burial lot is located.