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 ganization occurs in the hemisphere opposite to that upon which the blow was struck; a phenomenon to which the term "contre coup" has been aptly applied. The dura mater may now be removed and thrown back, by dividing it all round the margin of the skull, and separating its attachment to the crista galli with a pair of scissars; before we part, however, with this membrane, we should observe whether any osseous deposits, or other morbid alterations are visible in its texture; for such changes are not uncommon in the dura mater, especially in the falx: the tunica arachnoidea thus brought into view may present various morbid appearances; it may be opaque, or water may be found effused under it. . The pia mater often exhibits its veins turgid with blood, which indicates that some impediment had existed to the return of the circulation from the head to the heart. It is very important to distinguish between this appearance and that which is the result of the inflammation of the membrane; in this latter case, it should be remembered, that the small arterial branches are the vessels gorged with blood; and which are so multiplied as to form, by their numerous anastomoses, a beautiful network. In true inflammation also the membrane will be found thickened. There is still another source of fallacy with