CAIRO  History has proved that there are two subjects that will move Egyptians to pour into the streets in riotous numbers, crashing windows, burning cars, battling one another and defying an army of club-wielding riot police officers.

One is the price of bread. Another is soccer, as was proved again this week after Egypt’s national team was defeated by its bitter rival Algeria, losing a berth in the World Cup tournament next year and sparking a riot outside the Algerian Embassy in Cairo late Thursday night.

But there was a pronounced difference between the bread riots of 1977 and 2008 and the soccer riot of Thursday night: the government quieted those earlier outbreaks by quickly lowering the price of bread, while this week it stoked outrage against Algeria.

Egypt had defeated Algeria 2-0 in Cairo on Saturday to set up Wednesday’s climactic playoff in the Sudanese capital, Khartoum. After Egypt lost the second match, the government withdrew its ambassador from Algiers and accused Algerians of menacing Egyptian fans after the game. President Hosni Mubarak’s eldest son, Alaa, a wealthy businessman, sounded as if he were calling his nation to war.