We do not see how exertion could contribute to the attack at the exact moment when the testimony shows the attack occurred without contributing to its precipitation at that moment. It was stated in Hartford Accident Indemnity Co. v. Oglesby, 70 Ga. App. 160 ( 27 S.E.2d 774): "This court cannot say as a matter of law that a certain amount of physical exertion materially contributed to the death of one in whom a circulatory collapse had already begun because of a blood transfusion. On such a question, as shown by the record, medical experts disagree, and this court is not qualified to settle so controversial a question.

An award denying compensation will be affirmed where this connection is not made out. See Merritt v. Continental Casualty Ins. Co., 65 Ga. App. 826 ( 16 S.E.2d 612); Hartford Accident Indemnity Co. v. Oglesby, 70 Ga. App. 160 ( 27 S.E.2d 774); American Mutual Liability Co. v. Harden, 64 Ga. App. 593, 595 ( 13 S.E.2d 685). In the Oglesby case it was held as follows: "This court cannot say as a matter of law that a certain amount of physical exertion materially contributed to the death of one in whom a circulatory collapse had already begun because of a blood transfusion.