The plasma of the blood is replenished in its nutritive constituents by the food taken at frequent intervals. Water is necessary to render the blood sufficiently fluid, and to hold the other constituents in solution. The presence of certain chemical substances is also essential. Lime, iron, and certain other minerals, must also find a place. Besides these conditions, certain constituents manufactured in the body itself, as liver sugar and the corpuscles in normal quantity, are necessary to health. Water is more essential than food, and oxygen more than water. One deprived of food dies from impoverishment of the blood; if deprived of water death takes place much sooner, but if deprived of oxygen, death ensues within five to eight minutes. About a ton and a half in the shape of food and drink is added to the blood of an ordinary man during the year. As there is the same amount of waste, a ton and a half of material, therefore, must be carried out of the body through the blood during the same time. Some of the products of oxidation, as urea and carbonic acid gas, are very poisonous to the nervous system. Certain organs, as the kidneys, skin and lungs, are designed especially to remove these poisons from the current of the blood, and carry them out of the body.

If, through disease of these organs, they fail to perform their functions, the blood becomes highly charged with the poison, and, unless speedily relieved, death is the result. If the lungs fail to eliminate the carbonic acid, death results within a few minutes. If the kidneys fail to remove the urea, death must follow in a short time. The same is true if the skin fails in its office.

From the above it may readily be seen that the disorders of the blood are many. There may be too much blood, when the condition is called plethora; or too little, when it is called anaemia; or it may contain too much water, or too little; or too many red corpuscles or too few; or the plasma may be deficient in tissue-building constituents; or the blood may be poisoned by the retention of carbonic acid and urea.

Treatment

A considerable quantity and wide variety of food should be taken regularly. A sufficient amount of water and fluids should also be taken. Frequent baths and a reasonable amount of exercise are advised. The sleeping-room should be well ventilated, and plenty of fresh air supplied. Where the blood disease is due to disease of some particular organ, the latter requires primary attention.