SPECIFIC GRAVITY OF THE BRAIN. 
Ill 
ever the modus operand^ that marked or even complete relief 
is often afforded upon the development of mercurial action in 
the system.” ( Medical Circular , Jan. 1853.) 
ON THE SPECIFIC GRAVITY OF THE BRAIN. 
The following is the summary of an elaborate paper on 
this subject, by Dr. W. H. O. Sankey, of the London Fever 
Hospital : — 
“ Summary. — The foregoing analyses of 77 observations 
made upon the specific gravity of the brain, render probable 
the following general conclusions, viz. : 
ce That the mean specific gravity of the grey matter, in 
either sex, is 1 *034 ; that the density of the grey matter is 
somewhat below the mean in the earlier and later periods of 
life; that the highest density is met with between the ages 
of 15 and 30 years in males, and between £0 and 30 years in 
females ; that the density of the grey matter is, in a slight 
degree, lower in those persons who have died after a long 
illness, and greater, to a slight extent, in those subjects 
examined before twelve hours after death than in those 
examined at later periods. 
“ That the density of the grey matter may be found in a 
subject after death to be *006 below the mean, without any 
cerebral symptoms having been present during life; but 
when the specific gravity exceeds the mean by *006, then one 
of the following conditions has existed during life, viz., either 
acute cerebral disease, attended with head symptoms of the 
gravest character, or chronic disease, (in all the cases analysed 
of chronic disease of the kidneys,) attended either with no 
cerebral symptoms or only with slight delirium. 
“ That the mean specific gravity of the white matter after 
death is 1*041 ; that its density varies less than that of the 
grey matter in the sexes, or in the different periods of life ; 
that it is much less affected by post-mortem changes or 
length of the last illness. 
“ That in those cases in which the gravest cerebral 
symptoms were present during life, the density of the white 
matter after death may present two opposite conditions — 
either it may exceed the average, or it may be much below 
the mean. 
“ That high specific gravity of both grey and white matter 
is found in conjunction with those morbid conditions of the 
