Let him speak for himself.
"In earliest youth Demosthenes earned an opprobrious nickname by the effeminacy of his dress and manner." Does Mr Mitford know that Demosthenes denied this charge, and explained the nickname in a perfectly different manner?
(See the speech of Aeschines against Timarchus.) And, if he knew it, should he not have stated it?
He proceeds thus: "On emerging from minority, by the Athenian law, at five-and-twenty, he earned another opprobrious nickname by a prosecution of his guardians, which was considered as a dishonourable attempt to extort money from them." In the first place Demosthenes was not five-and-twenty years of age.

Mr Mitford might have learned, from so common a book as the Archaeologia of Archbishop Potter, that at twenty Athenian citizens were freed from the control of their guardians, and began to manage their own property.

The very speech of Demosthenes against his guardians proves most satisfactorily that he was under twenty.

In his speech against Midias, he says that when he undertook that prosecution he was quite a boy.

(Meirakullion on komide.) His youth might, therefore, excuse the step, even if it had been considered, as Mr Mitford says, a dishonourable attempt to extort money.