“Now I punch out of the edge of the check a few tiny disks.  I moisten the tip of a needle and press them carefully into the holes that make the upper part of the figure 3.  See, even in my haste and without glue, they fill the perforations completely and I can shake and pull the check without disturbing them.”

It was true.  The little plugs fitted perfectly, and even with the knowledge that they were there it was almost impossible to see where they had been inserted.

“Now,” continued the expert, “I merely take my punch and carefully punch enough holes to the right of the upper part of the figure 3 to make it a 5.  And there you are.  If I wanted to pass this check through the bank I would only have to complete the job by smearing a drop of the invisible glue over the back where I have plugged the original holes.  This glue is wonderfully tenacious and will actually hold the edges of paper together.  It needs only the smallest surface in order to get hold.  After it is on not even the microscope could detect it readily.  And no amount of pulling or shaking of the check will disturb it.

“You may suppose that a check that is stamped this way, for instance—­$600$—­would be hard to change into one of four figures.  But it is almost equally easy.  The crook simply punches out enough disks from the edge to fill up the last dollar mark completely, and after he has plugged it and the glue is dry he punches a cipher into the place and then punches a dollar mark after it.  Of course, after punching the little disks out of the edge of the check it is necessary to trim that part of the paper, but that is done readily, for checks always have ample margin.

“The check-raiser does not depend on the fact that the scrutiny of checks in a large bank is bound to be hasty, but he knows that he need not fear if his work is at all well done, for the paying teller simply cannot spend much time in examining the many checks that are passed in.

“One New York City bank sends through the clearing-house daily an average of 3,100 checks, and as there are about sixty-five such banks in the clearinghouse the total number of checks handled in the few hours of business in a day is something enormous.

“It is this haste—­which, by the way, is absolutely necessary in order to keep the books posted to date—­that is responsible for the passing of one of the most peculiar checks that ever came under the notice of the detectives of America.  In this case the check was neither falsified nor was the signature forged, but it was bogus just the same.

“It was a check made up of the parts of two checks, and all the implements necessary for falsification were a pair of scissors and that invisible glue.  The clever swindler had got hold of two genuine checks from the same bank.  One was for $1,000 and the other for $70.  Placing these two checks together, one on top of the other, he cut them through neatly with the scissors.  Then he pasted that portion