comparative lessons of brain wounds. 
305 
5. Leptomeningitis; 6. Intru-dural suppuration ; 7. Encepha¬ 
litis; S. Abscess; 9. Pyaemia; 10. Hernia-cerebri. 
Concussion , if unaccompanied by haemorrhage, is the natural 
sequence of injury or infraction of cerebral substance or its mem¬ 
branes. Contusion , on the contrary, designates a condition re¬ 
sultant upon rupture of blood-vessels, or laceration of the more 
minute and microscopic brain elements. Compression may result 
from effusion of blood, depressed portion of punctured vault, en¬ 
trance of foreign substances, hyperanemia, or exudations. Pachy¬ 
meningitis is critically described by chronic and local inflamma¬ 
tion of the dura resulting (secondarily) in thickening, new forma¬ 
tion, and (subsequently) necrosis of the osseous vault. Lepto¬ 
meningitis indicates acute or sub-acute inflammation of arachnoid 
and pia-mater arising from irritative agencies. Intra-dural sup¬ 
puration is a common sequel of putrescent coagula, necrosed 
bone, or other irritating and foreign substances. Traumatic en¬ 
cephalitis may develop from concussion or laceration either with or 
without deposit of bone spiculse and extraneous matters. Abscess , 
pyaemia and hernia-cerebri are secondary factors, lienee of con¬ 
nective and subjective importance merely. The direct complica¬ 
tions of cranial fracture, however, are encephalitis from injury of 
cerebral substance, and inter-cranial haemorrhages. 
From exhaustive and carefully compiled statistics prepared by 
Wharton, of Philadelphia, I have been able to formulate the per¬ 
centage of fatality attending the different classes (regional) of 
perforating injuries of the human cranium, as follows : 
Orbital, 17-18, or 94 per cent. 
Sphenoidal, 4-5, or 80 per cent. 
Occipital, 2-3, or 66 2-3 per cent. 
Parietal, 1-2, or 50 per cent. 
Frontal, 3-7, or 43 per cent. 
Temporal, 2-5, or 40 per cent. 
The showing is by no means satisfying. 
Examining the statistics more critically, I find the sub-diplo- 
etic or dural surface of the skull is invariably the greatest sufferer, 
in obedience to the well-known philosophical law, that injury fol¬ 
lows in the line of extension rather than that of compression. 
