Bernard,
When my son was a about one and a half, we were setting up the museum, and Brad and I were getting things ready for the Symposium, when my little man Alec took a header and scared the bejesus out of me. Luckily Brad (a more experienced dad) was there to calm me down, I was ready to rush the little guy to the emergency room, when it turned out all he had was a bruise.
Another time, Alec, who loves to run around up there, tripped and hit his face right next to his eye on the feet of the table on which the Saracen Castle diorama sits, giving himself a big black eye. He was fine, but both times I was out of my mind, blaming myself for not preventing him from falling. Now that he is almost 3, and has had the normal amount of bumps and bruises at school, on the playground, and playing with his little cousins and friends, I am finally used to it . . . although when I hear him cry, I still come running.