The THEORY behind vaccination and inoculation is the same as the one taught as Hatha Yoga by Shiva, or Mahadeva as he is often called. It is said of Mahadeva that he used to drink poison, and by doing so he got over its effect. Mahadeva was the most venturesome among the ascetics. He is pictured carrying a serpent round his neck. If one can be such friends with a serpent as to keep it round one's neck, one can no doubt sit comfortably in the presence of someone one does not like. The hatred and prejudice and nervousness which are felt in the presence of someone one does not like would then not arise. The soul which has forgotten its battle with everything that made it fear and tremble and run away, has conquered life and has become the master of life; it attains the kingdom of heaven. No doubt the methods which Mahadeva adopted were extreme measures; no one could recommend them to his pupils and be thought sane in this modern world!