"SEC. 1584. A domestic servant hired for a definite period and to be employed in the personal service of his master, or of the family of the latter, may leave the service or be discharged before the expiration of the term; but if the master dismisses the servant without sufficient cause, he shall indemnify him by paying him fifteen days wages in addition to the wages due.
"The amount of the wages of the domestic servant and the payment of the wages earned by him shall be established by the means of evidence recognized by law."