Clinical chemistry the denser blood cells and platelets to the bottom of the centrifuge tube, leaving the liquid serum fraction resting above the packed cells. This initial step before analysis has recently been included in instruments that operate on the "integrated system" principle. Plasma is in essence the same as serum, but is obtained by centrifuging the blood "without" clotting. Plasma is obtained by centrifugation "before" clotting occurs. The type of test required dictates what type of sample is used. A large medical laboratory will accept samples for up to about 700 different kinds of tests. Even the largest of laboratories rarely
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