Laws 1949, chapter 558, shall not be construed to apply in the case of employees known to have had tuberculosis as demonstrated by tuberculous lesions of the adult type or by demonstration of the germs of tuberculosis in such employee’s secretions or excretions previous to or at the time of employment in said institutions. Laws 1949, chapter 558, shall apply in the case of employees known to have only an allergic reaction to tuberculin or only evidence of a healed primary infection if they contract tuberculosis while employed in said institutions. Laws 1949, chapter 558, shall apply to all employees of said institutions who sustain an accidental inoculation of the germs of tuberculosis through the skin and become disabled thereby.