Griffith's 1928 experiments with Streptococcus pneumoniae demonstrated:

1. Griffith was perhaps the first person to show that hereditary information could be transferred horizontally rather than by descent. 2. In 1928 he reported the first demonstration of bacterial transformation. 3. Transformation is a process in which external DNA is taken up by a cell, thereby changing morphology and physiology. 4. He was working with Streptococcus pneumoniae, the bacterium that causes pneumonia. _Source: OpenStax Biology for AP(R) Courses (CC BY 4.0), Ch 14 'DNA Structure and Function', sections 14.1-14.6_