Emigration of educated manpower from the LDCs to the industrialized countries has long been the subject of intense debate, and attempts at policy intervention to affect the migration flows have been made at both the national and international levels . At the nationa1 level, the sending countries have tried to use devices such as making graduates post bonds when leaving for post-graduate training in industrialized countries, in order to put pressure on them to return home. The receiving countries have imposed strict controls on all kinds of immigration from the LDCs, including the immigration of educated manpower. These restrictions have sometimes been represented as reflecting a concern over the possibility that an excessive migration rate might harm the sending countries, though in reality they have probably resulted as much from pressure by domestic interest groups who have tried to forestall competition from immigrant manpower. In the 1970s, there was also extensive discussion of the possibility of introducing an internationally administered tax on migration, the proceeds of which would go to the sending countries. This proposal will be further discussed below.