I then walked slowly down the garden path, which happened to be composed of a clay soil, peculiarly suitable for taking impressions.

No doubt it appeared to you to be a mere trampled line of slush, but to my trained eyes every mark upon its surface had a meaning.

There is no branch of detective science which is so important and so much neglected as the art of tracing footsteps.
Happily, I have always laid great stress upon it, and much practice has made it second nature to me.

I saw the heavy footmarks of the constables, but I saw also the track of the two men who had first passed through the garden.

It was easy to tell that they had been before the others, because in places their marks had been entirely obliterated by the others coming upon the top of them.