Ireland was uniquely vulnerable to a failure of the potato crop
	in the 1840s.  Potatoes had been imported to Ireland in the late
	sixteenth century (they were brought to Europe from the Spanish
	empire in America).  By the nineteenth century, varieties adapted
	to the Irish climate were developed and they became a staple,
	particularly for the poor, who often lived off little else.

	An adult male would eat 12 to 14 pounds (5 to 6 kg) a day.
	If the amount seems large, it must be remembered that growing
	potatoes was back-breaking work.  Fields were dug with a spade;
	planting and fertilisation were done by hand.  An acre (about
	0.4 hectare) could support four people, about twice as many
	as the equivalent area of grain.  With a supplement of milk or
	buttermilk a diet like this did not lack any essential nutrients.

	The population of Ireland was growing at around 1.6% a year in the
	early nineteenth century (a rate that would cause it to double
	every 44 years).  This was one of the highest rates in Europe.
	The rate fell drastically in the fifteen years before the Famine
	to something like 0.6%.  Population growth was highest in the
	West, where small plots of intensively cultivated potatoes were
	the most common.  The population of Ireland reached its peak
	just before the Famine.

	Although the Irish poor may have been relatively healthy (there
	was a notable lack of scurvy), they were still appallingly
	poor.  It was common for labourers to hunger in the late summer
	before harvest.  In 1841 there were more than a million of them.
	Housing and clothing were poor: mud huts and rags were the norm
	for the majority.  Men lived to an average around 37 years of age,
	(actually not a short lifespan by European standards of the time).
	But most importantly, the Irish economy was ailing since the
	end of the Napoleonic wars and the poor were getting poorer.

	The Industrial Revolution never reached Ireland in the nineteenth
	century (with the exception of eastern parts of Ulster).
	Irish cottage industries could not compete against the new
	mills of England.  There was little opportunity for employment
	outside of agriculture and agriculture did not pay well.

	The potato blight was misunderstood or not understood at all.
	People could see that it thrived in damp weather, but the
	scientific committee of inquiry set up by Peel considered it a
	type of wet rot.  A fungicide for blight was not discovered until
	1882, when it was found that spraying a solution of "bluestone"
	(copper sulphate) prevented the disease from taking hold.  At
	the time of the famine there was nothing a farmer could do.

	Medical science could do no better.  There was no cure for
	the common relapsing fevers, never mind typhus and cholera,
	especially when these struck people already weak from hunger.

	It would have taken massive government intervention to feed
	everyone during the famine, probably more than any government
	of the time was capable of.  As it happened, the efforts of
	the government were wholly inadequate, even by the standards
	of the time.  The Treasury spent £8 million, mostly in the form
	of loans that were never repaid.  This amounts to around two to
	three percent of government spending during the period, or 0.3%
	of GNP.  It was easy for critics at the time to find more money
	spent on other things, including £20 million to "compensate"
	slave owners in the West Indies when their slaves were freed.