On Saturday last, I was called to a young woman who had dislocated the patella of the left knee joint outwards; the inner edge rested upon the outer surface of the external condyle, and was immoveably fixed, and caused great pain when touched. She says it was occasioned by her foot slipping backwards from one stair to another, and she immediately fell down. I commenced the reduction, as stated by Mr. Mayo, but I could only produce semiflexion, and that gave her great pain; insomuch that I was obliged to desist, and the patella remained in _statu quo_. But when the knee was thus semiflexed, I desired my assistant to extend the leg suddenly; and having my fingers on the patella at the time, and pressing it inwards, it immediately returned to its natural position. I must confess, sir, that I should have been afraid to have continued the flexion as described in Mr. Mayo's case, "by bending the knee to the utmost," fearing that the remedy might be worse than the disease, and the result proved that in this case it was not necessary. I remain, Sir, Your obedient servant, P. M. HOSKINGS. 168, Fleet-Street, Dec. 3d, 1828. VACCINATION. _To the Editor of the London Medical Gazette._ SIR, The mistake of the printer in substituting the word "every" for "even," in the paper on Vaccination (p. 40), so materially affects the sense of the passage, that I must request the favour of the following insertion:-- "3d. That while the vaccine cicatrix retains even one distinct fovea or depression, the individual continues unsusceptible both of small pox and of re-vaccination; but that," &c. I am, Sir, Your obedient servant, THOS. H. BURDER. 2, Brunswick Square, Dec. 15, 1828. SINGULAR BICEPS MUSCLE. _To the Editor of the London Medical Gazette._ SIR, The valuable paper communicated to your Journal, by Mr. Stanley, last week, has brought to my recollection a singular appearance of the parts in front of the shoulder-joint which I dissected about two years ago. It is a fact worth recording; and perhaps you will be kind enough to insert it in your next number. The circumstance was this--that in the right arm, instead of there being a biceps muscle having two origins, the one the shorter from the corocoid process, the other the longer from the upper part of the glenoid cavity of the scapula, there was simply a one-headed muscle arising from the corocoid process. I could find no tendon passing through the joint answering to the long head of the biceps, neither was there any appearance of a biceptical groove; the capsular ligament was, perhaps, thicker than it is found in ordinary cases. I knew nothing of this man during life, and am therefore unable to give any account of the use which he made of this arm. I am, your obedient servant, C. M. BURNETT. House Surgeon's Apartments, St. Bartholomew's Hospital, Dec. 8th. STETHOSCOPE. _To the Editors of the London Medical Gazette._ GENTLEMEN,