The employer shall cause every employee who while engaged in any work or process included in section two,¹ is exposed to lead dusts, lead fumes, or lead solutions, to be examined at least once a month, for the purpose of ascertaining if symptoms of lead-poisoning appear in any employee. The employee shall submit himself to the monthly examination, and to examination at such other times and places as he may reasonably be requested by the employer, and he shall fully and truly answer all questions bearing on lead-poisoning asked him by the examining physician. The examinations shall be made by a licensed physician, designated and paid by the employer, and shall be made during the working hours, a time allowance therefor at the employer's expense being made to each employee so examined.