him were twofold: he must not only
eat, he must avoid being eaten. It was probably a stickleback that took
his leg. A more powerful enemy would have taken the whole of him. So
intent was he on his quarry that he scarcely realized the severance until
he found himself swimming in an aimless lopsided circle. Then he sought
the friendly shelter of the weeds, and sat still to ruminate. The leg was
undoubtedly gone--his right hind leg--it was nipped off close to his body.
He felt no pain, but, the moment he left his support, he realized that he
was at a great disadvantage. The more studied his efforts to progress
straight, the more certainly abnormal was his course. In letting himself
sink slowly to the bottom he showed prudence. It was only at the bottom
that he was likely to escape notice.

He stayed there for a succession of days, getting hungrier and hungrier,
for it was only the smallest fry that came within his reach. It was lucky
for him that his gills lasted out. It was a full month before a new leg
commenced to fill the vacancy, and, by that time, they had shrunk from
feathery exuberance to two ugly stunted tufts. It was the most painful
period in his whole career. Every day his breathing grew more laboured.
Instinct told him to seek the surface, but, each time he made the effort,
he capsized before half the distance was accomplished. In six weeks' time
came relief. He had not yet secured a new leg, but the growing stump
fulfilled its purpose. He reached, by strenuous efforts, the surface of
the water, opened his mouth and _breathed the air_.

[Illustration: HE STAYED THERE FOR A SUCCESSION OF DAYS.]

But for his unfortunate accident, it is probable that the transformation
from a water-breathing to an air-breathing animal would have accomplished
itself imperceptibly. It is likely indeed, that, for a short period, while
his gills were decrepit, and his lungs infantile, he might have breathed
air and water alternately and at will. Now, however, his gills were, for
all practical purposes, useless; his lungs, ready but unpractised. The
necessity of air-breathing was forced on him at a moment's notice.

Small wonder that he commenced by overdoing matters. To begin with he
distended himself so that he could not sink at all. Then he sank with
far too small a reserve, and struggled to the surface spluttering and
half-drowned. It was only after much tribulation that he adjusted matters
to a nicety, diving with just suffici