In order to justify a court in coming to the conclusion that an
injury arose in the course of an employment, it is not enough to
show that the injury had something to do with the employment,
or that if it had not been for the fact that the worker was employed
by the particular employer in question he would not have received
the injury. An injury arises in the course of a worker's employment
only when it arises when the workman is doing something " which
is part of his service to his employer or master. No doubt it need not
be actual work, but it must, I think, be work, or the natural incidents
connected with the class of work - e.g., in the workman's case the
taking of meals during the hours of labour " (Charles R. Davidson
& Co. v. M'Robb (1), per Lord Dunedin). It is only when a work-
man is doing something which he was employed to do, or some-
thing which is incidental to that which he is employed to do, that
he is acting in the course of his employment - or, in other words,
"in effect the same thing - namely, when he is doing something in
discharge of a duty to his employer, directly or indirectly, imposed
upon him by his contract of service. The true ground upon which
the test should be based is a duty to the employer arising out of
the contract of employment, but it is to be borne in mind that the
word ' employment' as here used covers and includes things belong-
ing to or arising out of it. For instance, haymakers in a meadow
on a very hot day are, I think, doing a thing in the course of their
employment if they go for a short time to get some cool water to
drink to enable them to continue the work they are bound to do,
and without which they could not do that work, and workmen are
doing something in the course of their employment when they cease
working for the moment and sit down on their employer's premises
to eat food to enable them to continue their labours " (St. Helen's
Colliery Co.. Ltd. v. Hewitson (2), per Lord Atkinson). If the work-
man is engaged upon his own business, and not upon the business
of his employer, directly or indirectly, he cannot be said to be acting _
in the course of his employment.