Is a thumb-nail injury a direct and sole cause of death under an accident insurance policy?

In Mardorf v. Accident Ins. Co., [1903] 1 K.B. 584, the question was whether or not a person who was insured against injury by accidental violence and who had accidentally inflicted a wound on his leg with a thumb-nail, the leg later becoming inflamed and the individual later dying as a result of the wound, was covered. Was the injury there the direct and sole cause of his death? The court answered the question in the affirmative. In the words of Wright J. [p. 588]: … once it is agreed that the same instrument inflicted the wound and introduced the poison, it seems to me to follow that the morbid condition of the lungs which ultimately proved fatal was directly and solely caused by the wound. Take the case of a man being bitten by a mad dog and eventually dying of hydrophobia: surely it would be accurate to say that the death was directly and solely caused by the bite, although what immediately preceded the death was the disease resulting from the introduction of the poison into the system. It was found that the peril insured against was the direct cause of the man's death.