I get that the tulip thing it's over-blown, but...

"When the crash came, it was not because of naive and uninformed people entering the market, but probably through fears of oversupply and the unsustainability of the great price rise in the first five weeks of 1637."

So, what happened in January, 1637?

"So those who lost money in the February crash did so only notionally: they might not get paid later. Anyone who had both bought and sold a tulip on paper since the summer of 1636 had lost nothing. Only those waiting for payment were in trouble, and they were people able to bear the loss."

Does the author know how debts work?