How have courts interpreted the proviso of an accident policy in respect of death by accident or violence?

In Reynolds v. Accidental Ins. Co. (1870), 22 L.T. 820, the policy contained a proviso that no claim should be payable under the policy in respect of death by accident or violence, unless such death should be occasioned by some "external and material cause operating upon the person of the said insured" [p. 820]. The facts were that the insured, while in a pool about one foot deep, suddenly became insensible from some unexplained internal cause and fell into the water face downwards. The cause of death was suffocation by water. The plaintiff claim was successful. Willes J. at p. 821 held: "In this case the death resulted from the action of the water on the lungs and from the consequent interference with respiration … the fact of … falling in the water from sudden insensibility was an accident".