The partition which separated the yard from that of the house next door, was old, and in a very dilapidated condition, while that at the bottom was almost new, and was armed at the top with a row of bristling nails.

Bringing the powerful magnifying-glass I had brought with me for such a purpose, to bear upon it, I examined it carefully from end to end.

The result more than justified the labour.

A little more than half way along I discovered another small smear of blood.

There could be no doubt that the man had cut his finger on a nail as he had climbed over on his murderous errand.
The next and more important thing was to decide how this information was to be made useful to me.