To prosecute or pursue a particular avocation or form of business as a continuous and permanent occupation and substantial employment. A single act or business transaction is not sufficient, but the systematic and habitual repetition of the same act may be. Dry Goods Co. v. Lester, 60 Ark. 120, 29 S. W. 34, 27 L. It. A. 505, 40 Am. St. Rep. 102; State v. Tohnan, 100 La. 662. 31 South. 320; Holmes v. Holmes, 40 Conn. 120; Railroad Co. v. Attalla. 118 Ala. 362, 24 South. 450; Territory v. Harris, 8 Mont. 140, 19 Pac. 286; Sangster v. Ivav, 5 Exch. 386; Lawson v. State, 55 Ala. 118; Abel v. State, 90 Ala. 633, 8 South. 700; State v. Shipley, 98 Md. 657, 57 Atl. 12.