The Boy with the Cuckoo-Clock Heart (Electronic book text, New ed.)

"FIRSTLY: don't touch the hands of your cuckoo-clock heart. SECONDLY: master your anger. THIRDLY: never, ever fall in love. For if you do, the hour hand will poke through your skin, your bones will shatter, and your heart will break once more.
"
Edinburgh, 1874. Born with a frozen heart, Jack is near death when his mother abandons him to the care of Dr. Madeleine--witch doctor, midwife, protector of orphans--who saves Jack by placing a cuckoo clock in his chest. And it is in her orphanage that Jack grows up among tear-filled flasks, eggs containing memories, and a man with a musical spine.
As Jack gets older, Dr. Madeleine warns him that his heart is too fragile for strong emotions: he must never, ever fall in love. And, of course, this is exactly what he does: on his tenth birthday and with head-over-heels abandon. The object of his ardor is Miss Acacia--a bespectacled young street performer with a soul-stirring voice. But now Jack's life is doubly at risk--his heart is in danger and so is his safety after he injures the school bully in a fight for the affections of the beautiful singer.
Now begins a journey of escape and pursuit, from Edinburgh to Paris to Miss Acacia's home in Andalusia. Mathias Malzieu's "The Boy with the Cuckoo-Clock Heart" is a fantastical, wildly inventive tale of love and heartbreak--by turns poignant and funny--in which Jack finally learns the great joys, and ultimately the greater costs, of owning a fully formed heart.

"From the Hardcover edition."