He studied the developmental physiology with focus on the the critical developmental period. He found that a number of functions in the body must develop in the certain period of development, otherwise there are the changes in development or the disruption.

More about the personality of prof. Jiří Křeček and his work 

Prof. Jiří Křeček, M.D., D.Sc.

11. 4. 1923 – 30. 1. 2014