Korczak was a renowned doctor, specialising in paediatrics. Medical students came from far and wide to listen to his lectures. Korczak's personality and methods of teaching can best be illustrated by a lecture he gave at the Institute of Pedagogy in Warsaw entitled "The Heart of a Child":
"We were all surprised by Dr. Korczak's instruction to gather in the X Ray lab", one of his students recalls. The Doctor arrived bringing along a four year old boy from his orphanage. The X Ray machine was switched on and we see the boy's heart beating wildly. He was so frightened so many strange people, the dark room, the noise of the machine. Speaking very softly, so as not to add to the child's fears and deeply moved by what could be seen on the screen, Korczak told us "Don't ever forget this sight. How wildly a child's heart beats when he is frightened and this it does even more when reacting to an adult's anger with him, not to mention when he fears to be punished." Then heading for the door with the boy's hand in his, he added, "That is all for today!" We did not need to be told any more everybody will remember that lecture forever."
