His meaning was to gain the understanding that the unification of Germany will be brought about through the strength of the military forged in iron and the blood spilled through warfare.
"Iron and Blood" or "Eisen und Blut" is part of a speech given to the Prussian Parliament by Otto von Bismarck imploring the Parliament to increase the budget provided for military expenditures. The phrase which has been often transposed to "Blood and Iron".
His meaning was to gain the understanding that the unification of Germany will be brought about through the strength of the military forged in iron and the the blood spilled through warfare.