As there has been, from time to time, much written in your very interesting publication on the subject of the "Old Countess of Desmond," it may, perhaps, not be unacceptable that I should give you a description of an old family picture in my possession, said to be of that person, to which allusion has been made by some of your correspondents, especially by A. B. R., in your paper of Saturday, 14th February. The painting in question has been for a great number of years in the possession of my family, and from my earliest childhood I have heard it designated as that of the old "Countess of Desmond," although there is no mention of her name thereon. My father for a long time thought it was a work of Rembrandt; but on a close examination there was discovered the name of "G. Douw," low at the left-hand side; and since the picture has been cleaned, the signature has become more distinct. It is painted on board of dark-coloured oak, of eleven inches by eight and a half. The portrait, which reaches to below the bust, and represents a person sitting, is eight and a half inches in length; the face about two and three quarter inches. It is admitted by the best judges to be a painting of great merit. It represents, as well as it is possible, extreme old age, with an extraordinary degree of still remaining vigour, and in this respect certainly fits exactly the character of its subject. The dress is correctly described by your correspondent A. B. R. The forehead is not very high, but square and intellectual--deeply wrinkled; the nose is rather long, and very well formed; the eyes dark; the mouth compressed, and denoting quiet firmness; the expression altogether pleasing and placid, and the face one that must have been handsome in youth. Should any of your correspondents wish to see this picture, I shall leave it for a short time in the hands of my bookseller, Mr. Newman, 3. Bruton Street, Bond Street, who has kindly consented to take charge of it, and to show it to those who feel an interest in such matters. It must, at first sight, appear strange that such men as G. Douw, the painter of the picture in question, or Rembrandt to whom are attributed other portraits of this old lady, should have condescended to copy from other artists, (for the respective dates render it quite impossible they could have painted from life in this instance): however, it is natural to suppose that this extraordinary instance of longevity made great noise at the time of, and for some time after, her death, and that a correct representation of such a physical phenomenon, although the work of an inferior artist, may well have afforded a fitting study for even such eminent painters as Rembrandt and G. Douw.