What does Peter give the baby before they leave for Henrik’s boat?

Peter gives the baby a few drops of some kind of medicine to make her sleep.

Peter reached into his pocket and took something out. He went to the parents and leaned down toward the baby. He opened the lid
of the small bottle in his hand.
"Howmuch docs she weigh?"Peter asked.
"She was seven pounds when she was brn,"the young woman replied. "She's gained a little, but not very much. Maybe she weighs
eight pounds now, no more."
"A few drops will be enough, then. It has no taste. She won't even notice."