Ronnie Luther, age 11, of Speedway, Indiana., for his question:

What is blood plasma?

An average sized man contains about 5.‑1/2 quarts of busy blood in his body. It gathers up water and digested food from the walls of the intestines and oxygen from the 1ungs. It gathers up waste materials from the body and delivers them to the kidneys, skin and lungs. The heart is the trusty pump which keeps the blood stream circulating throughout the body. Almost three quarts of a man’s total blood supply is composed of red and white floating cells. The rest is the watery liquid called blood plasma.

The plasma is the liquid stream which carries the vital blood cells through the body. The blood itself is red because in every drop there are about 300 million floating red cells. In the same drop there are also more than 400,000 assorted white cells. The main job of the red cells is to carry life giving oxygen to the body tissues and gather up waste carbon dioxide. The white cells are mainly occupied with healing processes and with attacking diseases.

But the blood cells cannot move around by themselves. Without the liquid strewn of circulating plasma they would be helpless. And about 90% of this busy plasma is just plain water. The remaining ten par cent is dissolved chemicals, a vast assortment of highly complex chemicals without which the body would quickly perish. The plasma carries dissolved food and gathers up wastes and even helps the red cells in the process of respiration,

Nitrogen compounds, salts, sugars, fats, proteins, hormones and all sorts of antitoxins are but a few of the vital chemicals carried by the blood plasma. Wherever it flows the hungry, thirsty tissues grab what they want from the vital fluid and pour their waste materials into it. Most important, the concentration of chemicals in the plasma must be kept balanced. If the solution is too week, the red blood cells swell up and burst. If it as too strong, they shrivel and perish. The body has a number of ways to keep the chemical concentration of the plasma always in balance. It can rid itself of waste and excess materials It can lose and gain water.

The plasma totes waste materials to the kidneys which send them on out of the body. The plasma also loses chemicals and water in perspiration. New supplies of chemicals are poured an from the glands, from antitoxin medicines and from dissolved foods through the intestine walls. We replace the lost water to the plasma in the simplest way in the world ‑ merely by drinking. Our liquid food and drink are absorbed by the plasma through the walls of the intestines.