Section 50. Sections forty-seven and forty-eight shall not apply to (a) janitors; (b) employees whose duties include no work on Sunday other than (1) setting sponges in bakeries, (2) caring for live animals, (3) caring for machinery; (c) employees engaged in the preparation, printing, publication, sale or delivery of newspapers; (d) farm or personal service; (e) any labor called for by an emergency that could not reasonably have been anticipated; (f) pharmacists employed in drug stores.