s chased their leaders in a tireless pack, and so
also it was in the afternoon. Wedderburn was a little quieter than usual,
and Hill's face was hot all day, and his overcoat bulged with textbooks
and notebooks against the last moment's revision. And the next day, in the
morning and in the afternoon, was the practical examination, when sections
had to be cut and slides identified. In the morning Hill was depressed
because he knew he had cut a thick section, and in the afternoon came the
mysterious slip.

It was just the kind of thing that the botanical professor was always
doing. Like the income tax, it offered a premium to the cheat. It was a
preparation under the microscope, a little glass slip, held in its place
on the stage of the instrument by light steel clips, and the inscription
set forth that the slip was not to be moved. Each student was to go in
turn to it, sketch it, write in his book of answers what he considered it
to be, and return to his place. Now, to move such a slip is a thing one
can do by a chance movement of the finger, and in a fraction of a second.
The professor's reason for decreeing that the slip should not be moved
depended on the fact that the object he wanted identified was
characteristic of a certain tree stem. In the position in which it was
placed it was a difficult thing to recognise, but once the slip was moved
so as to bring other parts of the preparation into view, its nature was
obvious enough.

Hill came to this, flushed from a contest with staining re-agents, sat
down on the little stool before the microscope, turned the mirror to get
the best light, and then, out of sheer habit, shifted the slips. At once
he remembered the prohibition, and, with an almost continuous motion of
his hands, moved it back, and sat paralysed with astonishment at his
action.

Then, slowly, he turned his head. The professor was out of the room; the
demonstrator sat aloft on his impromptu rostrum, reading the _Q. Jour.
Mi. Sci_.; the rest of the examinees were busy, and with their backs to
him. Should he own up to the accident now? He knew quite clearly what the
thing was. It was a lenticel, a characteristic preparation from the
elder-tree. His eyes roved over his intent fellow-students, and Wedderburn
suddenly glanced over his shoulder at him with a queer expression in his
eyes. The mental excitement that had kept Hill at an abnormal pitch of
vigour these two days gave way to a curious nervous tension. H