▁the ▁Ap od aca - C anning ▁treat y ▁of ▁ 1 8 0 9 . ▁The ▁actions ▁of ▁Balt as ar ▁H idal go ▁de ▁C is ner os ▁in ▁Buenos ▁Aires ▁reflected ▁similar ▁out comes ▁em an ating ▁from ▁the ▁other ▁Spanish ▁cities ▁of ▁South ▁America . ▁ ▁Comp ared ▁to ▁other ▁parts ▁of ▁Latin ▁America , ▁sla very ▁played ▁a ▁much ▁less er ▁role ▁in ▁the ▁development ▁of ▁the ▁Argent ine ▁economy , ▁mostly ▁because ▁of ▁the ▁absence ▁of ▁gold ▁mines ▁and ▁sugar ▁plant ations , ▁which ▁would ▁have ▁demanded ▁huge ▁numbers ▁of ▁slave ▁workers . ▁Col onial ▁Brazil , ▁for ▁example , ▁imported ▁as ▁many ▁as ▁ 2 . 5 ▁million ▁Afr icans ▁in ▁the ▁ 1 8 th ▁century . ▁By ▁contrast , ▁an ▁estimated ▁ 1 0 0 , 0 0 0 ▁African ▁slaves ▁arrived ▁at ▁the ▁port ▁of ▁Buenos ▁Aires ▁in ▁the ▁ 1 7 th ▁and ▁ 1 8 th ▁centuries , ▁and ▁many ▁were ▁dest ined ▁for ▁Par agu ay , ▁Chile ▁and ▁Boliv ia . ▁ ▁The ▁colonial ▁liv est ock ▁ran ches ▁were ▁established ▁toward ▁the ▁middle ▁of ▁the ▁ 1 8 th ▁century . ▁The ▁pace ▁of ▁growth ▁in ▁the ▁region ▁increased ▁dram atically ▁with ▁the ▁establishment ▁in ▁ 1 7 7 6 ▁of ▁the ▁new ▁Vic ero yal ty ▁of ▁Rio ▁de ▁la ▁Pl ata ▁with ▁Buenos ▁Aires ▁as ▁its ▁capital , ▁and ▁increased ▁legal ▁trad ing ▁allowed ▁by ▁the ▁Free ▁Trade ▁Act ▁of ▁ 1 7 7 8 ,