Could I just point out that a microtome is a device for holding the material whilst it is being sectioned with a microtome knife (razor), rather than the knife itself. Here is a very simple version of one:
http://blog.makezine.com/archive/200.../microtome.gif
Microtome - Wikipedia, the free encyclopedia
Microtome Knives - Wikipedia, the free encyclopedia
It's possible that some of the wedges we love so much could also have started life as microtome knives too.
Sorry for being pedantic!