Here the deceased man was at work and therefore in the course of his employment at the time he vomited. But it only begs the question to say that that establishes he was injured by an accident in the course of his employment. No circumstance of the place or the employment had to exist for the vomiting or the rupture to occur. Counsel for the appellant argued strongly that that was an irrelevant consideration. He contended that "in the course of" must be given some meaning different from "out of", otherwise nothing would have been accomplished by the change from "and" to "or". This argument makes it necessary to examine the distinction between accidents arising out of and arising in the course of employment. It has been said that the words "arising out of" indicate a causal relation, and the words "in the course of" a temporal relation, with the employment. Perhaps the earliest and among the best known of such statements are those of Buckley L.J., as he then was, in Fitzgerald v. W. G. Clarke & Son [1] and Craske v. Wigan [2] , where he said: "the words "out of" point, I think, to the origin or cause of the accident; the words "in the course of" to the time, place, and circumstances under which the accident takes place". Viscount Haldane thought that this analysis was "unduly abstract", and said: "I doubt whether the time, place and circumstances can properly be so sharply distinguished from the conditions which are described as belonging to the origin and cause ": Thom or Simpson v. Sinclair [3] . His judgment was concerned with the nature of the causal element in the requirement that the accident must arise out of the employment and not with the nature of the requirement that it must (under the English Act) also arise in the course of the employment. The words I have quoted mean that considerations of time, place and the circumstances in which the accident occurred may be involved in "arising out of". They do not mean that time alone is involved in "in the course of". The most that, it seems to me, can be got from the many dicta in numerous cases in which the distinction between the two expressions is referred to is confirmation of Lord Wright's observation in Dover Navigation Co. Ltd. v. Isabella Craig [1] : "I do not know that attempts to amplify the language or define the dividing line have been very illuminating, though help in deciding any particular problem may be obtained by examining actual reported cases, not generally as laying down principles of law, but as showing how in particular circumstances of fact the dividing line has been drawn" [2] . The cases show that the term "accident arising out of and in the course of employment" had a wider connotation, and therefore a lesser denotation, than it would have had if either "out of" or "in the course of" had been omitted. But that does not mean that the two elements in the compound expression "arising out of and in the course of" were wholly independent and unrelated concepts. Now that the Commonwealth Parliament has put asunder the two expressions that formerly were joined in one, statements about the part each played when they were united, although still helpful, must be applied cautiously. Fitzgerald v. W. G. Clarke & Son [3] and Craske v. Wigan [4] were cases in which it was said that the accident arose in the course of, but not out of, the employment. In the former the accident occurred because of the practical joke of unruly workmates. It could not have occurred, however, unless the injured workman had been employed. In the latter a domestic servant was injured while present in the home, and thus in the course of her employment, although not at the particular time performing any duties. A cockchafer, attracted by the light in the room, came through the window, and so startled her that she threw up her hand and hit her eye. Suppose that, instead of a beetle, a bullet had come through the window and struck her - a ricochet from a rifle fired in a neighbouring field - the legal position must have been the same. Unless she had been where she was in the course of her employment, she would not have been alarmed by the beetle nor struck by the bullet. Yet the accident did not arise out of her employment, although it occurred in the course of it. The distinction between the facts in such cases and in others like Lawrence v. George Matthews Ltd. [1] may seem a fine one; for in that case injury by a tree falling on to the road was held to arise out of the employment. But the judgment of Russell L.J., as he then was, which was quoted by Lord Wright in Dover Navigation Co. v. Isabella Craig [2] emphasized that there is a distinction between a danger casually occurring in a place and a danger causally connected with the place as a place - that is to say, a danger arising from some quality of the place itself. Any accidental injury caused to a worker by contact with part of the premises where he works - as, for example, from a wall falling down, or by his slipping on the floor - is now regarded as arising out of his employment. This may (where the conjunct phrase prevails) have capricious results, as was recognized by the Privy Council in the case arising from the New Zealand earthquake (Brooker v. Thomas Borthwick and Sons (Australasia) Ltd. [3] ). But it was the ground on which the accidents there in question were held to have arisen out of, as well as in the course of, the employments. So too, when a man in an epileptic fit fell into a water-filled furrow and was drowned, and when in another case a sufferer from diabetes collapsed against a part of the machinery where he worked and was thus injured, the accidents arose out of and in the course of their employments: Wilson v. Chatterton [4] ; Smith v. Australian Woollen Mills Ltd. [5] . As was said in the joint judgment of Gavan Duffy C.J., Rich, Dixon, Evatt and McTiernan JJ. in the latter case, "the form, nature and extent of the injury sustained when the appellant fell were determined by a characteristic feature of the premises where he was obliged to work" [6] . On the other hand, things coming from outside the premises, such as beetles, bombs, bullets and lightning (apart from cases of special exposure to the risk) can cause injuries without the place being dangerous as a place, and without any physical contact with the place contributing to the injury. In such cases the accident, although it arises in the course of the employment, does not arise out of it. For, to establish that an accident arose out of a man's employment, it is, Viscount Haldane said, in Thom or Simpson v. Sinclair [7] not enough that something happened to him "which would not have happened to him if his employment had not caused him to be in the place at which the accident occurred at the time of its occurrence, the place and time having thus been conditions of the result brought into existence by the employment" [8] . More than that is necessary to constitute the kind of causal connexion that the words "arising out of" postulate. Viscount Haldane's judgment explains the sense of the word cause that is involved in the statement that the words "arising out of" express a causal relationship. More importantly for present purposes, it also states convincingly that the employment may be a necessary condition without which the accident could not have occurred and yet not, in the relevant sense, causally associated with it. This, in my view, disposes of the argument that to read "in the course of" as meaning that the employment was a condition sine qua non of the accident is to give it the same meaning as the phrase "arising out of" has. Law may at times seem to flounder somewhat when it approaches questions of causation, professing to avoid philosophic consideration of what is essentially a problem of philosophy. Law must, for its purposes, extract one or more circumstances out of the whole complex of antecedent conditions of an event as its cause. I adverted to this in connexion with worker's compensation law, especially in relation to the cause of death, in The Commonwealth v. Butler [1] and in Hussey's Case [2] . It is not necessary to discuss it here. The distinction between conditions that provide the setting without which an event could not have happened and the concept of cause here adopted may not be easily formulated. But it is, I think, correct to say, as has been recently said in learned discussions of this topic, that the distinction is "an inseparable feature of the historian's and the lawyer's and the plain man's use of causal notions", and as "obstinately marked by common sense", however it may be criticized philosophically: Causation in the Law, by Professor H. L. A. Hart and Mr. A. M. Honoré, at page 10; and an article by the same authors (1956) 72 L.Q.R., at p. 73.