nissan, do a test for me....

Gather a serrated steak knife that is 3-4 years old from your kitchen, nice and used....then get a brand new straight razor.

Extend your left arm, cut it with the serrated steak knife with moderate pressure.
Watch the bleeding and observe how long it takes to quit.

Now move down the arm 6 inches, again cut yourself with the same moderate pressure only this time with straightrazor.
Watch the gushing blood, and observe how long it takes to quit ( if it ever does)


The reasoning is simple, bleeding stops from coagulation...meaning proteins form with platelets from the blood to form a clot. The more cells damaged(dull head tearing tissue) the more platelets sent to cut and the clot forms faster.....less cells damaged (clean cut) means less platelets, and the cut cant adequately heal itself as quickly....the blood just keeps flowing.

If you cant accept that for an answer I can find an article where a scientist says it in bigger words, if that will make anyone feel better about it.