just as Luca della Robbia was held responsible for every bit of glazed terra-cotta.  These ascriptions to the most fashionable and lucrative names had become conventional, and had to be destroyed.  Invaluable service has been rendered by reducing the number given to Donatello and adding to the number properly ascribed to others.  But the process has gone too far.  The difficulties are, of course, great, and stylistic data offer the only starting-point; but as these data are readily found by comparison with Donatello’s accepted work, it ought to be possible, on the fair and natural assumption that Donatello may well have made such busts, to determine the authenticity of a certain proportion.  In any case, it would be less difficult to prove that Donatello did, than that he did not make statues of this description.  Among the busts of very young boys which cannot be assigned to Donatello are those belonging to Herr Benda in Vienna, and to M.G.  Dreyfus in Paris.  Nothing can exceed their softness and delicacy of modelling, and they are among the most winning statuettes in the world.  They were frequently copied by Desiderio and his entourage.  One of the little heads in the Vanchettoni Chapel at Florence is likewise animated by a similar exemplar.  There is something girlish about them, a pursuit of prettiness which is no doubt the source of their singular attraction, and which invests them with an irresistible charm.  The San Giovannino, also in the Vanchettoni, is a more concrete version of childhood, but is by the same hand as its fellow.  These four busts fail to characterise the child’s head; not indeed that characterisation was needed to make an enchanting work, but that Donatello’s children elsewhere show more of the individual touches of the master and personal notes of the child.  The Duke of Westminster possesses a life-sized head of a boy,[155] which is palpably by Donatello, though no document exists to prove it.  We have all the essentials of Donatello’s modelling; the handling is uncompromising and firm; the child is treated more like a portrait.  Indeed, many of these children’s busts, even when symbolised by St. John’s rough tunic, were avowed portraits—­the Martelli San Giovannino, for instance, which from Vasari’s time has been ascribed, and probably with justice, to Donatello.  This little head enjoys a reputation which it scarcely deserves.  The expression is dull, the hair grows so low that scarcely any forehead is visible; the cheeks bulge out, and the mouth is too small.  We have, in fact, a lifelike presentment of some boy, perhaps of the Martelli family, showing him at his least prepossessing moment, when the bloom of childhood has passed away, and before the lines have been fined down and merged into the stronger contours of youth.  Desiderio would have improved Nature by modifying the boy’s features, and we should have had a work comparable to those previously mentioned.  But Donatello (and perhaps his patrons) preferred a less idealised version.