Saunaka says that probably the head of the foetus is first developed since head is the only organ that makes the functions of all other organs possible. Kritaviryya says, it is the heart that is first developed since heart is the seat of Manah and Buddhi (mind and intellect). The son of Parásara says that the development of the umbilical region of foetus must necessarily precede (that of any other part of its body) inasmuch as it is through umbilical chord that an embryo draws its substance from mother's body. Márkandeya says that the hands and feet of a foetus are first to be developed since they are the only means of movements in the womb. Subhuti Gautama says that the development of the trunk is the earliest in point of time since all other limbs and organs lie soldered to and imbedded in that part of the body. But all these are not really the fact. Dhanvantari holds that the development of all the parts of the body of an embryo goes on simultaneously; and they can not be perceived or detected in their earlier stages of development in the womb owing to their extremely attenuated size like a mango fruit or sprouts of bamboo. As the stone, marrow, pith etc. of a ripe and matured mango-fruit or the sprouts of bamboo, cannot be separately perceived in the earlier stage of their growth but are quite distinguishable in the course of their development, likewise in the early stage of pregnancy the limbs and organs of the body (foetus) are not perceptible for their extremely attenuated stage but become potent (and therefore they are distinctly perceived) in the course of time for their development. 18.
* Sometimes it passes from the body of the child to that of the mother and vice versa.
Now we shall describe the parts and principles of the body of a foetus which are respectively contributed by the paternal element, maternal factor, the serum (Rasaja),the soul (Atmaja), the natural (Sattvaja) and the innate physiological conditions (Sátmyaja). The hairs of the head and body, beard and moustaches, bones, nails, teeth, veins (Sira), nerves, arteries (Dhamani), semen and all the steady and hard substances (in the organism of a child) are contributed by the paternal element in the conception Pitraja; whereas flesh, blood, fat, marrow, heart, umbilicus, liver, spleen, intestines, anus (Guda) and all other soft matters in the body owe their origin to the maternal element (Mátrija); strength, complexion, growth, rotundity and decay of the body arc due to the serum (Rasaja). The sensual organs, conciousness, knowledge, wisdom, duration of life (longivity), pleasure and pain etc. are the outcome of the spiritual element in man (Atmaja). We shall describe the Sattvaja features of the body in the next chapter. Valour, healthfulness, strength, glow and memory are the products of a child naturally born with physiological conditions of the parents (Sátmyaja). 19.