increase was occurring all over the Eastern Mediterranean, not just in Palestine... The increase in Muslim population had little or nothing to do with Jewish immigration. In fact the province that experienced the greatest Jewish population growth (by .035 annually), Jerusalem Sanjak, was the province with the lowest rate of growth of Muslim population (.009).Fred M. Gottheil has questioned McCarthy's estimates of immigration. Gottheil says that McCarthy didn't give proper weight to the importance of economic incentives at the time, and that McCarthy cites Roberto Bachi's estimates as conclusive numbers, rather than lower bounds based on detected illegal immigration. Gad Gilbar has also concluded that the prosperity of Palestine in the 45–50 years before World War I was a result of the modernization and growth of the economy owing to its integration with the world economy and especially with the economies of Europe. Although the reasons for growth were exogenous to Palestine the bearers were not waves of Jewish immigration, foreign intervention nor Ottoman reforms but "primarily local Arab Muslims and Christians." However, Gilbar did attribute the rapid growth of Jaffa and Haifa in the final three decades of Ottoman rule in part to migration, writing that "both attracted population from the rural and urban surroundings and immigrants from outside Palestine." Yehoshua Porath believes that the notion of "large-scale immigration of Arabs from the neighboring countries" is a myth "proposed by Zionist writers". He writes: As all the research by historian Fares Abdul Rahim and geographers of modern Palestine shows, the Arab population began to grow again in the middle of the nineteenth century. That growth resulted from a new factor: the demographic revolution. Until the 1850s there was no "natural" increase of the population, but this began to change when modern medical treatment was introduced and modern hospitals were established, both by the Ottoman authorities and by the foreign Christian missionaries. The number of births remained steady but infant mortality decreased. This was the main reason for Arab population growth. ... No one would doubt that some migrant workers came to Palestine from Syria and Trans-Jordan and remained there. But one has to add to this that there were migrations in the opposite direction as well. For example, a tradition developed in Hebron to go to study and work in Cairo, with the result that a permanent community of Hebronites had been living in Cairo since the fifteenth century.