What is the test for determining whether there is a causal connection between the conditions under which an employee is required to perform his work and the resulting injury?

In Matter of McCarter v. La Rock, supra, this court said that it was thoroughly committed to an interpretation of our present statute which requires as the basis for an award a causal connection, apparent to a reasonable mind upon consideration of all the circumstances, between the conditions under which the work is required to be performed and the resulting injury; injury from an accident which need not have been foreseen or expected but which after the event must appear to have had its origin in a risk incidental to the employment and to have flowed from that [246 N.Y. 287]source as a rational consequence, and that there must be more than a mere location of the employee in the pathway of an accident entirely disconnected from his employment.'