Body fluid and lymph in Ayurveda.
In human beings, body is formed by solids and fluids. The fluid part is more than 2/3rd of the whole body. Water forms most of the fluid part of the body. The total water in the body is about 40 lit. It is distributed into two major fluid compartments, one is intracellular fluid (50%) and other is extra cellular fluid (45%).
In Ayurveda, body fluid is rasa dhaatu, rakta dhaatu, lasikaa, and so on. Rakta dhaatu is compared with blood, lasikaa is compared with lymph. According to Ayurveda Rasa dhatu is the 1st dhatu which is made of aahara rasa. Rakta dhaatu is the 2nd dhatu which is develops from Rasa dhatu by the action of respective dhaatwaagni. This process is explained by Ksheerdadhi nyaaya, Kedaarekulya nyaaya and Khalekapot nyaaya.
Also it is doubtful if lasikaa can be interpreted as lymph. This is because wide range of functions of lymph is not hidden. Ayurveda in those days was quite advanced medical science. It seems impossible that compendia would not mention a word directly or indirectly about functions of lasikaa. Somehow references mentioned above do not include clues regarding such wide range of functions. Hence, it will not be wise to interpret lasikaa as lymph.