200 
HISTOLOGY OF ANIMALS. 
all the parts of the bone in the neighbourhood of the 
cells, becoming at the same time thin and transparent 
from the removal of the granules of earthy matter. In 
a vertical section of the lower end of the tibia, from a 
case of mollifies ossium ; the walls of the bone are ex- 
ceedingly thin, and so soft as to be readily cut with a 
knife, the entire medullary cavity, and all that remains 
of the cancellated structure, being full of oil and adipose 
tissue. 
There are still one or two more examples of fatty 
degeneration of tissues, of sufficient importance to merit 
notice. The first of these is a deposit of fatty matter 
between the layers of the cornea, giving rise to the 
arcus senilis. The discovery of the true nature of this 
change, which is common in the eyes of old people, is 
due to Mr. Canton, who has published an account of it 
in the “ Lancet” for 1850. 
In a vertical section of a cornea, given to me by 
Mr. Canton, the arcus senilis has formed, and be- 
tween some of the layers of which the cornea is com- 
posed there is a deposit of small, highly-refracting glo- 
bules of oil. The arcus is not situated in that part of 
the cornea joining the sclerotic, but a little nearer the 
centre, there being generally a transparent zone between 
the sclerotic and the arc. The last example of degenera- 
tion of tissues of which I shall speak, is the formation of 
Adipocire, which takes place after death, when flesh 
is exposed to a certain amount of moisture, or to a 
running stream of water. A preparation of the thigh of 
