Section 141. Every person operating a factory, shop or mechanical establishment where machinery is used for any manufacturing or other purpose except for elevators, or for heating or hoisting apparatus, shall keep and maintain, free of expense to the employees, such medical or surgical chest, or both, as shall be required by the department, containing plasters, bandages, absorbent cotton, gauze, and all other necessary medicines, instruments and appliances for the treatment of persons injured or taken ill upon the premises. Every such person employing one hundred or more persons shall, if so required by the department, provide accommodations satisfactory to it for the treatment of persons injured or taken ill upon the premises, and also suitable and sanitary facilities for heating or warming food to be consumed by those employees of the factory, shop or mechanical establishment who so desire. Every person carrying on a mercantile establishment where twenty or more persons are employed shall in the manner aforesaid provide such medical and surgical chest as the department may require. Whoever violates any provision hereof shall be punished by a fine of not less than five nor more than five hundred dollars for every week during which such violation continues.