Research in recent decades has ruled out such theories. Although it is true that blacks made up an important part of the armies and militias of the 19th century, they were not the majority nor did their number differ much from that of amerindians and whites, even in the lower ranks (the so-called cannon fodder). Nor did the yellow fever epidemics that affected Buenos Aires (especially the most lethal, which was that of 1871) have a big effect, since demographic studies do not support that view (on the contrary, they show that the most affected were recent European immigrants living in poverty) and, furthermore, this theory does not explain the decline of the black population in the rest of Argentina.