Blood.

Aimed at a general audience this film is about the structure and function of blood, focusing on the red and white blood cells and the plasma. Opening credits, microscopic shots of blood flowing through capillaries. Commentary explains that there are five hundred red corpuscles to every white and how blood cells can be separated from the plasma by centrifuge, as shown. Red Blood cells. Commentry explains that five million red corpuscles exist in every cubic millimetre of blood. The scale of a cubic millimetre is compared to an old penny, and the volume of five million is compared to a crowd of ninety thousand people at a football match, one fifth of five million. Diagrams show the function of red corpuscles during respiration. White blood cells. Commentary explains their function as microscopic footage shows a white corpsucle engulfing bacteria. Plasma. Water content of the human body is illustrated by squeezing juice from a potato, and an overlay image of a little girl in a graduated cyclinder. Commentary explains that plasma is mainly water neccessary for chemical reactions. Clotting of blood is demonstrated as blood is warmed and the plasma turns into jelly.