In Franklin’s published works there is a short essay called “A Conjecture as to the Cause of the Heat of the Blood in Health and of the Cold and Hot Fits of Some Fevers.” The blood is heated, he says, by friction in the action of the heart, by the distention and contraction of the arteries, and by being forced through minute vessels. This essay is very ingenious and well written, and the position given to it in his works might lead one to suppose that it was of importance; but I am informed by physicians that it was merely the revamping of an ancient theory held long before his time, and quite without foundation. Franklin’s excursions into the domain of medicine are not, therefore, to be considered among his valuable contributions to the welfare of man, except so far as they encouraged him to advocate fresh air and ventilation, though they may have assisted him to take better care of his own health. Of the numerous portraits of him of varying merit, nearly all of which have been reproduced over and over again, only a few deserve consideration for the light they throw on his appearance and character. The Sumner portrait, as it used to be called, is supposed to have been painted in London in 1726, when he was there as a young journeyman printer, twenty years old, and was brought by him to America and given to his brother John, of Rhode Island. He evidently dressed himself for this picture in clothes he was not in the habit of wearing at his work; for he appears in a large wig, a long, decorated coat and waistcoat, with a mass of white ruffles on his bosom and conspicuous wrist-bands. The rotund and strongly developed figure is well displayed. Great firmness and determination are shown in the mouth and lower part of the face. The animal forces are evidently strong. The face is somewhat frank, and at the same time very shrewd. The eyes are larger than in the later portraits, which is not surprising, for eyes are apt to grow smaller in appearance with age. This portrait, which is now in Memorial Hall at Harvard University, has been supposed by some critics not to be a portrait of Franklin at all. How, they ask, could Franklin, who was barely able to earn his living at that time, and whose companions were borrowing a large part of his spare money, afford to have an oil-painting made of himself in such expensive costume? and why is there no mention of this portrait in any of his writings? But, on the other hand, the portrait has the peculiar set expression of the mouth and the long chin which were so characteristic of Franklin; and it would have been entirely possible for him to have borrowed the clothes and had the picture painted cheaply or as a kindness. It is not well painted, need not have been expensive, and, as there were no photographs then, paintings were the only way by which people could give their likenesses to relatives.