The word lymph comes from the Latin word lympha. Lymph means clear water. The clear and alkaline collar that provides nutrients and protects cells is called lymph. It is yellowish or colorless and keeps the cells moist. Its relative importance is about 1.01-1.016 and pH 7.4-9.0. The volume of lymph is almost double that of blood ie 10-12 liters. It always flows in one direction.