Many of the poems in Sing-Song cover familiar childhood experiences, including many sweet, touching, and funny subjects. But the poems often take a dark turn, familiar to Victorians for whom the living and dead existed side by side.
For example, a poem about a bird:
A bedtime poem from which there is no waking:
Darkness in children's literature is a hot topic lately, but it's nothing new. Dystopians reflect teens' fears and perceptions about society, but also their hope -- they are the ones who redeem the corrupt societies portrays. Cursing in YA reflects the way some teens speak, but certainly doesn't expose them to words they would otherwise never hear. And absent parents in middle grade and YA reflect, for many, reality, and for others, a chance to learn about how other kids solve their own problems and make their own decisions.
Children's literature has always dealt with death -- fairy tales are notoriously grisly in their original versions, and the origins of many nursery rhymes is similarly macabre. And Victorian childhood, despite its sentimentalization in popular images, was a risky world, where infant and maternal mortality was an ever present risk. Literature for children reflected that then, just as it reflects the darker side of our world now.