Besides explaining at a stroke both the moral tone and the sophisticated vocabulary of Peter Rabbit, her remark draws attention to the fact that children's literature as we know it is a very new idea. It was the vastly increased amount of time at the disposal of children which steadily encouraged the growth of juvenile libraries. Today so many books for children are published that many parents find it hard to distinguish between great books and dross.
It may help to characterise the colourful and varied mass of modern children's books as plants in a garden. Fairy and folk tales are the grass: the basis for storytellers' imagination, staying around century in and century out, getting worn and ragged in places. The passing fads which often attract far more attention than they deserve, and quickly run to seed, are the annuals: today Sweet Valley High and the Animals Of Farthing Wood, yesterday Biggles and Dr Dolittle, 100 years ago Henty's deeds of derring-do and Empire. Some achieve perennial status - The Wind in the Willows, Tove Jansson's Moomintrolls, Tintin and Asterix, The Secret Garden. Then there are the shrubs, the books that have become seriously dug in, have even crossed frontiers: Pinocchio, Heidi, Babar, for example. Finally the classics: trees that tower above the rest, pruned, shaped, sometimes defoliated but still determined presences - Treasure Island, Robinson Crusoe and Gulliver's Travels.
It's worth reflecting, when we hear claims that too much rubbish is written for children, that any garden would be found wanting without these several elements. What we need is balance: too many annuals and a child's mind is threatened by the bright monotony of a municipal roundabout; too much nostalgia and high-minded morality and it finds itself lurking forlornly in a shrubbery of laurels.
But although I can see the need for variety in children's literature today, my feeling is that the newest plantings have rather lost sight of one essential function of the Child's Garden of Literature: its role in locating the child in the society in which he or she is growing up; the part it traditionally played in civilising the child.
Consider the genesis and fate of three classic children's stories that all once furnished the element of civilite. First, Pinocchio. Few people outside Italy realise that this famous story was written by a political satirist. He started writing instalments of The Story of a Puppet for a children's magazine founded by a friend in 1881 in an attempt to educate Italian children as one nation rather than a collection of regions. One eminent Italian scholar, Glauco Cambon, likened its impact on the Italian people to that of Dante or Manzoni because of its rich idiomatic legacy.
But even more important than its idiom to the Italians was its satire on the corruption of policemen, judges and other authority figures. Collodi's theme is the way in which an irresponsible, lying puppet learns to see through such plausible villains as the Cat and the Fox, and graduates into becoming a boy by acknowledging his responsibilities to society and getting a job in order to look after his sick and ageing parents. Today this interesting and, given current anxieties about family responsibilities and awareness of national corruption, extraordinarily relevant tale has been debased into crude accounts of a puppet whose nose grows longer every time he lies.
Heidi has fared little better. It was also written in 1881, by Joanna Spyri, who belonged to a circle of liberal-minded Zurich intellectuals. Her Heidi is a robust, clear-sighted little girl who pulls off her clothes as she climbs the Alm, declaring that she'd rather be dressed like the goats.
But it is essential to the story that besides revelling in natural freedom, she learns to read, and to tolerate urban life. Conversely, Clara Susemann, symbolically crippled by her stifling urban existence, finds health and freedom in the alps. Heidi is as typical of the nation that produced it as Pinocchio is of Italy: a hymn of praise for the high mountains, for sturdy peasant values and freedom from oppression, but also emphasising the need for the stubbornly individual grandfather to rejoin the social group of the village.
Heidi was immensely successful, but its sequels - not by Joanna Spyri - diluted its force: they had Heidi growing up, marrying the inane Peter, having children, and becoming a sententious hausfrau. Foreign language sequels bordered on the bizarre. Heidi Detective and Heidi in Tokyo are the most surprising of an astonishing range of alternative Heidis.
Finally, Jean de Brunhoff's Babar stories. Read in order, these form a carefully structured world. The first is a proper fairy-tale. Babar loses his mother, goes on a journey, finds a substitute for her in the Old Lady, matures through education and the civilising experience of the city world - recognisably Paris, complete with Grands Magasins - then returns to his home bearing gifts and wealth, but unlike most fairy stories, Jean de Brunhoff continues the saga to tell us exactly what happens when Babar and Celeste live happily ever after.
The five sequels - Babar's Travels, Babar the King, Babar and his Friend Zephyr, Babar at Home, and Babar and Father Christmas - provided children, and their parents, with as complete an advice system as a childcare manual. More complete, in fact, than a modem manual, because de Brunhoff was concerned with moral order, good manners and self discipline in a way which has currently become rather unfashionable.
The modern coda to the Babar tiles is a disappointing one. Laurent de Brunhoff continued in his father's footsteps when he grew up, and the series carried an enjoyably enough, but steadily losing its sense of purpose. In one of the most recent, we find Babar's youngest daughter Isabelle rollerskating along with a Walkman on her head, and Babar and Celeste degenerating from regal wisdom to harassed modern parents, chasing after naughty children.
What has been lost in the retelling of these stories is the purpose of civilising humankind. The bulk of new writing for children today falls into two camps: the world of extreme fantasy and the intense world of the family. Video games and television soaps echo that split. We have lost the centre: the use of stories to acquaint our children, to remind ourselves, of our position in and responsibility towards our immediate social world - in short, to civilise them.
But then we have also lost, in these days of demoralised political ideologies which cry freedom but find only corruption, a clear vision of what civilisation is, or could be. We are good at huge causes such as saving the planet and preaching international brother and sisterhood under the skin, but hollow on clearly graspable local identity. Do we even know, in this time of crisis in educational principles and abrupt decline in the availability of jobs for school-leavers, what the role of our children is going to be in tomorrow's world?
Nobody would wish for a return to the days of Mrs Trimmer, but can it be healthy that the closest we get today to the medieval courtesy books is probably the hypochondriac and sex-obsessed Diary of a Teenage Health Freak? Perhaps it isn't surprising that we let so many of our children slip away from adult influence into the Land of Mordor where the shadows dwell. Perhaps we have nothing to say to them.