"For a while, Himmler and Frank toyed with the idea of sending the Jews to the Indian Ocean island of Madagascar, which the Polish government had already considered; it was agreed that this could happen only after the war. Then Hitler spoke of concentrating them on the new Poland's eastern frontier, between the Vistula and the Bug. Later, Siberia was mentioned. In the meantime, the Lublin district became a kind of dumping ground for deported Jews, tens of thousands of whom were crowded into hastily constructed camps, while the supposedly transitional ghettos of Lodz, Warsaw, Lowicz and Glowno took on a more permanent quality. Not that they could have endured indefinitely. For one thing, they were intolerably cramped; a third of the population of Warsaw was crammed into 2.4 per cent of the city's residential area. At the same time, food rations for Jews were reduced so that by 1941 their daily calorific content was just over 25 per cent of the standard Polish allocation and a meagre 7 per cent of the German, far less than the subsistence minimum. Overcrowding and underfeeding were themselves intended to be lethal - which indeed they were, with mortality rates soaring to 10 per cent in Warsaw in 1941. 'It's high time that this rabble is driven together in ghettos,' declared Himmler, 'and then plague will creep in and they'll croak.' In the summer of 1942 Frank described sentencing 1.2 million Jews to death by starvation as 'just a marginal issue'."