The excitement of an infant is the changing of the rhythm; for the infant has no control over its own rhythm. It goes on at a greater and greater speed, until it cries or laughs. And the laughter or the cry is just the same. On the one side the infant will laugh and on the other side cry, because its rhythm is not normal. It can only be brought to a normal condition by the guardian's effort. But if one gets agitated or does not like the infant or is displeased with it, then one cannot help it.