This contention is without merit. The cases of Early v. Houser Houser, 28 Ga. App. 24 ( 109 S.E. 914); Callahan v. Carlson, 85 Ga. App. 4, 15 ( 67 S.E.2d 726); and Barber v. Rich's, Inc., 92 Ga. App. 880, 884 ( 90 S.E.2d 666), cited by defendants, are not apposite here. Those cases held that one who voluntarily undertakes to perform service for a master at the request of a servant who has no authority to employ other servants, is a mere volunteer and the master does not owe him any duty except not to injure him wilfully and wantonly after his peril is discovered.

2. (a) The contention of the defendant company that the plaintiff's decedent was a volunteer as to the company is predicated upon the principle of law that: "One who, without any employment whatever, but at the request of a servant who has no authority to employ other servants, voluntarily undertakes to perform service for a master is a mere volunteer, and the master does not owe him any duty, except that which he owes to a trespasser, — that is, not to injure him wilfully or wantonly after his peril is discovered." Central of Ga. R. Co. v. Mullins, 7 Ga. App. 381 (1) ( 66 S.E. 1028); Atlanta c. R. Co. v. West, 121 Ga. 641 ( 49 S.E. 711, 67 LRA 701, 104 ASR 179); Early v. Houser Houser, 28 Ga. App. 24 ( 109 S.E. 914); Barber v. Rich's, Inc., 92 Ga. App. 880 ( 90 S.E.2d 666). As held in Southern R. Co. v. Benton, 57 Ga. App. 520, 523 ( 196 S.E. 256), however, this principle of law has no application to a case such as this which is not based on the theory that at the time of the injury, the plaintiff's decedent was a servant of the defendant company, employed by an agent of the defendant company authorized to employ other servants; but rather, is based on the theory that the decedent had an interest in the subject matter sufficient to authorize him to lend his assistance to the company's employee.

1. The liability of the defendant for the plaintiff's injuries occurring within the defendant's place of business is partially dependent upon the status of the plaintiff in the store. To support his contention that the plaintiff was merely a volunteer to whom the defendant owed only the duty not to wilfully and wantonly injure him, the defendant in error cites Early v. Houser, 28 Ga. App. 24 (2) ( 109 S.E. 914); Barber v. Rich's, Inc., 92 Ga. App. 880, 884 ( 90 S.E.2d 66); Carstarphen v. Ivey, 66 Ga. App. 865 ( 19 S.E.2d 341); and Callahan v. Carlson, 85 Ga. App. 4, 15 ( 67 S.E.2d 726). These cases are all distinguishable from the present case by the fact that the act or acts which the visitors were performing were either not sufficiently related to the owner's or occupant's business or were not for the visitor's benefit, as well as the owner's or occupant's benefit. The mutuality of interest required to make one on the premises of another an invitee does not mean that there must be a commercial business transaction between the parties, but merely that each party is moved by a lawful purpose or interest in the object and subject matter of the invitation; the enterprise must be mutual to the extent that each party is lawfully interested therein, or that there is common interest or mutual advantage involved.