I'll bet biker doc is old enough to remember injector razor blades taped half their length and shirts with removable colar staves, eh?
And single edge razor like is used today as a scrapper stuck in the crack between the heel of a leather soled shoe (would you believe such a blade showed up on the field of a highschool foot ball came in a players shoe when I was in high school? and yes he was sent to the showers)
We had some cut nail fans around here ( and while I ain't nameing names they still are) for a bit.
There is currently another topic or two discussing the use of small knives for slashing and the effectiveness of such. Some discard shallow slashing as pointless. Visit an emergency room on say a Friday payday, checks came out, fleets in, full moon (huh, last night!) and look around a bit.......
-kBob