27. Hence it follows, that the operation we are considering, when skilfully performed, never gives rise to any dangerous or disagreeable affections. Experience has proved the truth of this assertion in the practice of Theden, Simson, Gooch, Broomfield, Bell, and Desault, the latter of whom performed the operation five times with complete success. The only case in which he was less fortunate, was that of a man, in whom the wound of the integuments closed up at first without any accident, but which was succeeded by two abscesses, one in the thigh, and the other in the leg, but without any affection of the interior of the joint. This patient was subject to a wandering rheumatism, which oftentimes attacked the lower extremities, and was perhaps in the present case the chief cause of the unfavourable occurrences. 28. It is to the English that we are indebted for the first operation performed for the extraction of these bodies. An account of this is given in the Transactions of a society in Edinburgh. Since that, the operation has been frequently repeated, and more than ten instances of it were already on record, when Desault first performed it in France. His method, somewhat different from that of others, was as follows. 1st, The patient must be laid on a bed, or seated on a high chair. The first position, however, is to be preferred, because when it is adopted, the patient need not be moved after the operation. 2dly, The leg is extended on the thigh, in order to relax the anterior part of the capsule of the joint. 3dly, The surgeon then searches for the foreign body, moves it to the internal side of the joint, against the attachment of the capsule, and secures it between his thumb and the fore-finger of his left hand, while an assistant draws the skin over the fore part of the rotula. 4thly, Taking then a common bistoury, he makes, on the protuberance formed by the body, a longitudinal incision of an extent proportioned to its size, through both the integuments and the capsule, so as to lay the body bare at the first stroke. 5thly, Sometimes the body escapes immediately of its own accord, in consequence of the compression made on it by the fingers. If its passage out be not spontaneous, a small scoop or a taper-pointed spatula passed under it, answers the purpose of extracting it. But, in the introduction of these instruments, it is necessary to avoid touching the articulating surfaces with their ends, lest, by being irritated, they might swell, and give rise to troublesome accidents. 6. If any resistance be met with, enlarge the opening and the extraction will become easy. Without this precaution, the edges of the wound, being bruised and irritated by the passage of the body, will swell, inflame, and unite again with difficulty.