Jenner's invaluable experiments, beginning in 1796 with the vaccination of eight-year-old James Phipps, proved that cowpox provided immunity ag...
…………………………………………………………………………………………………………. यो मुलुक सिंगापुर जस्तो बनिसकेको छैन मात्र राजनीतिक परिवर्तन...