Explaining The Physiology Of Blood Red, White Cells
( Originally Published 1936 )
Diseases of the blood are commonly supposed by the laity to manifest themselves largely by eruptions on the skin. According to this theory the blood, when diseased, carried impurities around and these impurities affect many organs, especially the skin.
In actuality, this theory breaks down almost completely. However much certain skin diseases may be due to internal derangements, nothing can be proved wrong with the blood in most instances. And when impurities can be demonstrated in the blood the skin is not regularly affected at all.
The blood is an organ, just as much as the liver is. In fact, it can be called a system just as much as the digestive system or the circulatory system. It is subject to all the diseases to which any other system is liable—it has tumors, and degenerations, and inflammations, etc. Besides that, of course, it is liable to a certain special disease of its own, dependent on its peculiar anatomy. This is loss of some part of its substance from hemorrhage, resulting in secondary anemia.
In order to understand the diseases of the blood, some knowledge of its physiology must be gained. The blood, as it flows in the vessels, is a tissue. The difference between it and all other tissues is that it is liquid and movable and the others are solid and stationary. But, like other tissues, it consists of cells set in an intercellular substance, the blood serum.
The cells of the blood are of two general kinds—the reds and the whites. The reds are in the majority. There is a very even concentration of them, the normal amount being measured in units of 5,000,000. In other words, if one took a certain definite amount of blood—a very small amount—from any part of the body and counted the red cells it contains, these would always be, in health, 5,000,000. This procedure can bd done very rapidly and does not necessitate the counting of 5,000,000' cells.
The white cells number 5,000 for the same amount. And they are constant in health and evenly distributed in the body.
These cells are born in the bone marrow and develop there to maturity. When they reach maturity, they are thrust out into the blood stream. After a short life they are destroyed—the red cells in the spleen and the white cells in various places.
There is another cell-like structure in the blood called the "plate-let." It is unique among bodily structures in that it does not appear to be a cell, although it is living matter. Its function is the highly important one of clotting the blood.
The blood system, therefore, consists of the bone marrow, the blood, and the spleen.
WHERE ARE RED BLOOD CELLS MANUFACTURED IN BODY
One department of medicine which has made extremely rapid progress in the last few years is that of diseases of the blood and blood-forming organs. The spurt in research has probably been due to the discovery of a specific treatment for the most serious form of anemia—so-called "pernicious anemia," now no longer pernicious.
Before outlining these researches, it might be worth while to note briefly the main features of our knowledge of the physiology of the blood.
The blood is essentially a fluid in which float a number of cells. The fluid is called the "serum." The cells are of different sorts; the most numerous are the red cells, and it is diminution in these cells which we mean when we say "anemia." The other elements are the white cells and platelets which, for the sake of brevity, we will not discuss here.
The life history of a red cell is interesting and important to an understanding of the anemias. The blood is constantly being replenished with red cells and they are constantly being destroyed. The place in the body where the red cells are formed is the bone marrow. And from this bone marrow many billion cells are thrown into the blood stream a day.
The place where the red blood cells are destroyed is the spleen. Some, of course, are lost from small cuts on the skin, or nose bleed, or, in the case of women, the monthly flow, but most of the cells are destroyed in the spleen. After destruction their coloring matter, which is mostly made from iron, is carried to the liver and there very largely converted into bile. The amount of bile which is formed a day is a rough index of the enormous number of red cells which are destroyed.
In health, this process of formation and destruction is very evenly balanced, so that the number of red cells is held in very definite con-centration at about five million per ccm. We can see that this balance would be destroyed either by something which would depress the productive activity of the marrow, or increase the destructive activity of the spleen. Both things actually occur.