Oct. 27 (UPI) -- Google is celebrating Bulgarian physician and microbiologist Dr. Stamen Grigorov with a new Doodle Tuesday, on what would have been his 142nd birthday.
Grigorov, who was born in 1878 in the village of Studen Izvor in the Trun region of Bulgaria, is the first scientist to discover the bacterium essential to the fermentation of yogurt. He also helped with the development of the first tuberculosis vaccine.