Lymph is a biological fluid present in a human’s body and this fluid has a somewhat similar composition to that of the plasma, present between the cells and tissues. It is colourless in nature and flows through the lymphatic system of a human’s body. It is composed of lymph nodes and lymph vessels or channels. This liquid flows in the empty space between tissue structures, the student can consider it as a sponge. Like water fills the spaces in a sponge, the interstitial fluid fills the cavities between the cells, this fluid lubricates and nourishes in the cells of all the tissues.