The action of the Argentine Government and the provincial authorities has been restrained, apart from the earliest period of the establishment of the Santa Fe colonies, both as regards the securing of immigrants, the distribution of lands, and the administration of the colonies.[101] Colonization has been, on the whole, a private affair. The work of organizing colonization has at times been undertaken by the proprietors themselves; they leased pieces of land and got a good price for them, at the same time increasing the surplus value of the plots they kept for themselves by promoting the increase of population. Sometimes it was undertaken by Colonization Companies, which bought land to divide and sell. More frequently it was undertaken by merchants who advanced credit to the colonists they settled, on condition that the colonists bought what they needed of the merchants, and entrusted them with the sale of their crops. The migration of the Santa Fe colonists was partly due to, and sustained by, a corresponding migration of merchants who had acquired wealth in the older colonies, and who thus got a larger body of customers. The merchant who organizes colonization often acts as the intermediary between the owner and the colonist, guaranteeing the owner a fixed rent for his land and receiving so much per cent. of his harvest from the farmer. This system is very widespread in the corn belt, but it is found all over the plain of the Pampas. It tends to disappear when the colony is older and deeper-rooted, as the colonist gradually earns his independence; he buys his lease, his equipment, and his furniture, and controls the sale of his own crops. In the districts where he has not become owner, the leases are generally variations of two types: farming leases, where the colonist has capital enough for working, and renting leases, where the capital is provided by the owner or the middleman. [101] The Agricultural Centres Law, passed in 1887 by the province of Buenos Aires to encourage colonization, has not had good results. By the terms of this law, owners who professed themselves willing to devote their lands to colonization received an advance on the value of the lands in the form of mortgages, the interest and repayment of the mortgage being charged to the colonists. Many owners took advantage of the law, but, after a pretence of colonization, kept the ownership of their lands.