Apparatus of Snakes. 
125 
once to cease, it soon assumes a white dead appearance, and 
a process of decay or absorption is instituted at its base, 
which only ceases on the fall of the tooth from its alveolus. 
During these changes the reserve fang has not been idle—its 
base has been gradually advancing, and it finally takes up its 
position and becomes fixed, close by the side of the injured 
one. By this time the poison duct has become detached from 
its old adhesions and is ready to form new, and when this 
process has taken place and the old tooth dropped off, the 
snake is once more fully armed and prepared for action. 
The place which the old fang occupied is now left vacant, 
but this will in time be occupied by the next reserve tooth 
which is called upon to supply the place of an injured one ; 
and when this in its turn drops oft', its place again will be 
left vacant, till the next reserve is required. A system of 
alternation is thus instituted by which a place is always kept 
open to which the reserve may advance, and hence we as fre¬ 
quently find the vacant space on the one side as on the other 
of the fixed fang. I am not aware that this alternation in the 
position of the fang is mentioned in books, but I write from 
numerous dissections aud preparations, and of these, the 
view here given, is the result. 
From the large corps de-reserve with which the poison 
fangs are supplied, it will at once be evident, that their ex¬ 
traction cannot, as was formerly supposed, render the snake 
permanently harmless. The thorough accomplishment how¬ 
ever of this object could easily be effected by the removal of 
the whole, or at least the anterior half, of the upper jaw—a 
simple operation, and one which could readily be performed 
with a pair of strong scissors. 
Another point of interest in connexion with the poison 
tooth is the development of the canal for which it is so re¬ 
markable ; and for the elucidation of this subject, the 
“ reserves” afford an admirable field of observation, as we 
Q 2 
