The proper quality of the plasma alone regulates the speed of blood circulation and ensures its entrance into the finest capillaries—the ultimate branches of the blood-vessels—hence, its capacity to carry supplies of nutriment to the tissues. The disturbance of this proper quality is among the main factors of constitutional disease.
2. The lymphoid tissue: The lymph is another of the life-giving liquids of the body, which through a vascular system of its own, draws certain nutritive substances from the food and carries them to certain organs which it feeds, especially the nerves.
After this slow task is completed, the rest of the lymph enters the blood and is carried by it to other parts of the body where only smaller quantities of lymph are needed for nourishing purposes.
The proper quality and chemical composition of the lymph, which is different from that of the blood, is of no less importance than that of the plasma for the preservation and regeneration of the organism.
What the plasma is to the blood, the lymph is to the nerves.
3. The nerve tissue: A particular aggregation of cells forms the nerves, which, emanating from their center in the brain and spine, run as another separate system all through the body.
This system, however, is not one of vessels; but the nerves may best be compared to the wires of a telephone system, establishing connection between the remotest parts of the body and its central point, from which the directions for both voluntary and involuntary movement are given and transmitted through the nerves.
They are of a peculiar chemical composition in which the nerve fat (lecithin) plays a very important part, since its frequent presence in insufficient quantity is among the most common causes of a great number of nervous and other diseases.
4. The bone tissue: The bones consist of a special and very distinct tissue in which lime predominates. This gives them the strength and solidity which enables them to act as support to all the other organs.
The bones too are fed by the blood, and it is through the blood that the necessary constituent parts for the regeneration of their tissue is conveyed to them.