CHAPTER II. 
SECTION I. 
TRAUMATIC LESIONS. 
The old division established for traumatic lesions must be retained: 
when they are considered from the point of view of their mode of re- 
pair and of the therapeutical measures they require: thus we recognize 
external, open or exposed traumatic lesions, in which the teguments— 
skin or mucous membranes—are divided; and internal, subcutaneous, or 
interstitial lesions, which are without solution of continuity of the skin 
or internal mucous membranes. Both kinds may open in pre-existing 
cavities or in natural reservoirs or canals ; then they are called wounds 
of cavities (plaies cavitaires), and are divided into external and internal. 
All traumatic lesions offer for consideration in its walls three zones : 
1. A modified or gangrenous zone, whose existence is constant but extent 
variable. At times, when it is very limited, and represented by little 
necrobotic parts or reduced to the thin layer of the anatomical ele-. 
ments, which have directly received the action of the disturbing body 
(cuts, pricks), it does not prevent immediate reunion ; at other times, 
when it is very extensive, is formed of crushed tissues, and infil- 
trated with blood and serosity, in which the blood-vessels are de- 
stroyed, severe complications are to be expected. 2. A zone called 
stupefied (stupefiée) or ischemic, which surrounds the preceding, and in 
which the tissues have lost their vitality, a zone in which the elements. 
can recover their activity quickly, but which, on the contrary, becomes. 
easily a prey to gangrene if severe phlegmasic phenomena occur. 3. A 
zone of irritation, peripherical, which is going to be the seat of great 
hyperemia, exudation, and leucocytic immigration more or less 
abundant, where began the changes leading to the separation of the 
wound, and from which start those which complete it (Verneuil). 
These complex phenomena which accompany traumatic lesions show 
peculiarities which depend upon numerous causes ; upon their exposure 
to the air or the protection of the wound by the tegumentary mem- 
brane, upon their extent, their depth, the nature of the involved struc- 
tures and the seriousness of the hurt they received ; upon their aseptic 
state or the interference of pathogeneous micro-organisms, and also. 
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