The 1913 Immigrants Regulation Act effectively ensured that new immigrants to South Africa would be white. Having established that only white people could be considered as potential new citizens, two questions then emerged: firstly, who was white, and, secondly, what kind of whites should be allowed to cross the borders of the Union? The answers came into particularly sharp focus in the debate over Jewish immigration in the 1920s and 1930s.

The immigration of Jewish people to South Africa was nothing new. Jews were among the first Europeans to arrive in South Africa, and were also part of the contingent of 1820 settlers. By 1880 the Jewish population had grown to about 4 000, most of whom were from Germany and Britain. Attracted by the mining revolution of the late nineteenth century, and pushed out of eastern Europe (particularly Russia and Lithuania) by anti-Semitic pogroms, the Jewish population of the colonies that would become South Africa had reached about 38 000 by 1904. By 1911, after the formation of the Union, it had grown to almost 50 000, or 3.7% of the white population.

Anti-Semitism was ‘deeply embedded in the South African experience’. Although reports on the undesirability of Jewish immigrants and discriminatory immigration practices by individual officials appear in debates around the introduction of the 1913 Act, the post-Union state, and the colonies that formed it, never formally (or otherwise) made systematic attempts to specifically exclude Jews. The anti-Semitic discourses and anti-Jewish immigrant actions of the 1920s and 1930s therefore reflected a significant shift in state policy and practice.

The new racial concerns focused on Jewish immigrants, that emerged at the end of the First World War fears took place in period that has been called the golden age of racial science and eugenics. These were, therefore, articulated in a new idiom, through the ‘scientific’ language of racial science and eugenics. Certain white immigrants were held to contaminate the [white] body, and blood or ‘stocks’ of the nation.