what is the meaning of this Google Doodle

The Google Doodle honoured German analytical chemist Friedlieb Ferdinand Runge (February 8, 1794 -25 March 1867)  on his 225th birth anniversary Thursday. Runge is best remembered for identifying caffeine, the psychoactive drug present in coffee beans which is responsible for stimulating the central nervous system.

He was the young scientist who started his work in his adulation age. He make revolutionary change in the field of chemical science.