Nothing in this Article shall be construed to prohibit the giving or offering of any bonus or extra compensation to any manager, coach, or professional player, or to any league, association, or conference for the purpose of encouraging such manager, coach, or player to a higher degree of skill, ability, or diligence in the performance of his duties. (1921, c. 23, s. 7; C.S., s. 4499(f); 1951, c. 364, s. 7; 1961, c. 1054, s. 6.)