32. The signs discriminative of the nature of luxations of the humerus, are not always accompanied by the same degree of certainty as those that announce merely its existence. Thus, nothing is more difficult than to determine when a luxation inward is primitive, and when it is consecutive, the same phenomena being common to both. Nothing but an exact history of the disease, stating the order in which the phenomena have succeeded each other, can throw light on this point, which is the more interesting and important, as, according to the one or the other state of things, the processes of reduction ought to vary. In the first case, the head re-enters its natural cavity by a short route; whereas, in the second, it arrives there by a much longer one. If, as Petit pretended, there exist luxations backward, sometimes primitive, and sometimes consecutive, the same remark may be applied to them with equal propriety. 33. Certain signs, common to luxations of the humerus, fractures of its neck, and dislocations of the scapulary extremity of the clavicle, might here create some uncertainty, if in the one, the absence of a tumour under the arm-pit, and of a depression under the acromion, did not prevent a mistake, which Hippocrates declared to be easily committed, into which, according to Galen, the masters of the art of wrestling fell, and which Pare cautions us to avoid; and if, in the other, the appearances proper to a fracture, did not prevent a mistake which would be serious in its consequences, and which sometimes results from the direction of the humerus, and the kind of protuberance formed in the arm-pit, by the end of the inferior fragment. (_See Fracture of the neck of the humerus_). § V. OF ACCIDENTS PRODUCED BY THE LUXATION. 34. Luxations of the humerus are but rarely followed by any serious accidents. Sometimes a swelling more or less considerable appears, immediately after the fall, in and around the arm-pit. This is the effect of an increased irritability of the part, and is seldom of long duration. Desault’s remedy for it was the application of compresses wet with vegeto-mineral water, or of cataplasms moistened with the same liquid. 35. Several authors, particularly Bell, speak (as if it were a familiar accident) of an œdematous swelling of the whole upper extremity, caused, in inward luxations, by a compression of the axillary glands. This phenomenon has not often occurred in the Hotel-Dieu, except in luxations of long standing: and when it has been met with in certain cases, very happy effects have been produced, by the action, continued for several days, of a roller applied with considerable tightness after the reduction, and reaching from the fingers to the arm-pit.