Siddhaswarupananda Paramahamsa's video lecture:The Body Is Not Constant, But You Are

Recent studies on the turnover of the molecular population within a given nerve cell have indicated that, although the cells themselves retain their individuality, their macromolecular contingent is renewed about ten thousand times in a lifetime. (In other words, the matter making up each cell is completely renewed every three days).

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Siddhaswarupananda Paramahamsa's video lecture: The Body Is Not Constant, But You Are