occurrence of these injuries has undoubtedly increased in frequency
with the employment of bullets of small calibre, and no other class of
case more strikingly illustrates the localised nature of the lesions
produced by small projectiles of high velocity. Again, no other series
of injuries affords such obvious indications of the firm and resistent
nature of the cicatricial tissue formed in the process of repair of
small-calibre wounds, and in none is the advantage of a conservative and
expectant attitude so forcibly impressed upon the surgeon. Implication
of the nerves may be primary, or secondary to an injury which left them
originally unscathed.

_Nature of the anatomical lesions._--In degree these vary in
mathematical progression, but the extent of the lesion is not always
readily differentiated by the early clinical manifestations, and again
the actual damage is not to be estimated by the gross apparent
anatomical lesion alone; but, in addition, consists in part in changes
of a less easily demonstrable nature, varying with the velocity with
which the bullet was travelling and the consequent comparative degree of
vibratory force to which the nerve has been subjected. In these
injuries, as in those of every part of the nervous system, the degree of
velocity appears to gain especial importance both in regard to the
general symptoms and the local effect on the functional capacity of the
nerve.

This is perhaps a fitting place for the introduction of a few further
remarks as to the significance of the term 'concussion' in connection
with the injuries produced by bullets of small calibre, since the most
striking exemplification of the results following the transmission of
the vibratory force of the projectile is afforded by the behaviour of
the comparatively densely ensheathed and supported peripheral nerves.

As already pointed out in Chapters VII. and VIII. the chief concussion
effects on the nervous tissue of the brain and spinal cord are of a
destructive nature, far exceeding those accompanying the injuries
designated by the same term seen in the ordinary accidents met with in
civil practice, and this damage is comparatively localised in extent.

In the case of the peripheral nerves I have still employed the terms
'concussion' and 'contusion' to designate certain groups of symptoms and
clinical phenomena, but any sharp distinction between the two conditions
on a morbid anatomical basis is impossible. The results of