TIIIS papcr deals with a series of GO consecutive cases treated by the aiithor during the last two years, and refers almost entirely t o gunshot injuries. From a practical point of vicw 1 have thought it bettcr t o direct attention to a n unselected series of cases, pointing out the difficiilties of treatment and the causes of failure, rather than t o attempt a literary review of the work of other surgeons. At the present moment the material for the latter attcmpt is lacking, owing t o the fact that only small groups of cases have been published. On considering one's own work, and in discussing the matter with others, one derives the impression that a general feeling of discouragenient and îailure has prevented piiblication : but further reflection makes i t an obvious duty t o enquire into the whole matter, in orùer that the causes of such failiire may be undcrstood, and avoideù or overcome in thc future.
REMARKS ON THE CAUSES, INCIDENTS, AND NATURAL RESULTS OF UNUNITED FRACTURES.There are certain obvious causes of non-union of fractures, and others which are more obscure, depending upon altered vital conditions of the bone-producing cells which are, a t present, matters, of speculation ratlier tlian observation. 1 propose in this paper to deal chiefly with the obvious causes, which could be rccognized in al1 the cases in the present series.Sucli causes are four in number, viz. : ( 1 ) Primary loss qf substance (34 cases) ; (2) Necrosis or secondary loss of substance ( 3 cases) ; ( 3 ) Displacement, zvith intervention ?f mft pnrts (21 cases) ; (4) Eburnation or sclerosis ( 2 cases). -This cause is the most important, and accounts for more cases than al1 the others put together, viz., 34 (56.6 pcr cent). In the bones-c.g., the radius, ulna, and tibia-whcre there is another parallel bone which maintains the length of the limb and prcvents contraction from bringing about a closure of the gap, the reason for loss of substance leading t o non-union is obvious. Whatever niay be Our conceptions as t o osteogene
