Fetal bovine serum specific cell type. When changing from batch to batch it is usual to adapt the cells to the new batch of material, for example, by mixing 50% of the old serum with 50% of the new serum and allowing the cells to acclimatise to the new material. Serum is stored frozen to preserve the stability of components such as growth factors. When serum is thawed, some precipitation may be seen. This is a normal phenomenon and it does not compromise the quality of serum in any way. The precipitate may be removed by transferring the serum to sterile tubes and
Blood, toil, tears, and sweat The motion passed unanimously. This was the first of three speeches which he gave during the period of the Battle of France, which commenced on 10 May. Churchill had used similar phrases earlier, such as "Their sweat, their tears, their blood" in 1931, and "new structures of national life erected upon blood, sweat, and tears". Churchill's sentence, "I have nothing to offer but blood, toil, tears, and sweat," has been called a paraphrase of one uttered on 2 July 1849 by Giuseppe Garibaldi when rallying his revolutionary forces in Rome: "I offer hunger, thirst, forced marches, battle, and death." As