Caspar Netscher, 'Two Boys blowing Bubbles', about 1670

A velvet curtain is drawn back from a stone window to reveal a little boy, who gazes upwards at a bubble floating past him and into the darkness. His eyes are wide and his long, fair curls frame his chubby cheeks. He leans on the sill to steady himself, and his other hand holds his hat – perhaps hoping to reach up and let the bubble come to rest on it. His concentration is total and focused on the fragile bubble.

The boy is dressed in the ornate fashion of the 1670s: rich fabrics – lace and satin – and deep gold bows and ribbons at neck and elbow. White and gold ostrich feathers adorn his hat. On the shelf by his hand are shells and a silver tazza, all costly objects of great interest to collectors and highly prized. An almost identical tazza can be seen today in the Rijksmuseum, Amsterdam.

In the shadows behind, a smaller child concentrates equally fiercely. Using a long pipe, he blows bubbles in the soapy liquid held in a cockle shell. Already a tiny iridescent sphere is forming. Pictures of this kind were popular in the Netherlands in the seventeenth century, bought for their charm, probably for a nostalgia for childhood and for an artist’s skill in the depiction of rich fabrics, transparent bubbles and the children’s faces, hair and expressive eyes.

But these paintings are known as homo bulla (‘man is a bubble’). Because bubbles burst so quickly, they are allegories intended to suggest the brevity of life. The silver tazza we see here may carry a message too – that gathering earthly possessions is a futile act in the face of mortality. Caspar Netscher painted several of these pictures; one portrays a lone boy seen through a stone window (now in the Mauritshuis, The Hague). He’s similarly dressed and looks up at a bubble he has blown himself; the tube he has used points up in its direction. By his side is a small rose, often used by painters as another symbol of how short life is, its petals already falling.

This tradition of the homo bulla reaches back into medieval times when the children were portrayed nude and with wings, as putti. The Dutch, although embracing the homo bulla as a life warning, seem to have preferred their children more realistic and fully clad, often very fashionably dressed. The theme was still popular in the eighteenth century, perhaps most famously in Soap Bubbles by Jean Siméon-Chardin (National Gallery of Art, Washington).