ENCLOSED IN THE TUSKS OF THE ELEPHANT. 63 



Upon as another instance indicating the existence of a system 

 of laws regulating the relations between healthy and morbid 

 tissues — laws which have been specidated upon, but have 

 never been sufiiciently investigated by anatomists. 



Having now given the anatomical characters of the ab- 

 normal ivory which invariably surrounds musket-buUets and 

 other foreign bodies which lodge in the pulps of the tusks of 

 the elephant, I shall proceed to state the various conditions 

 under which these enter the organ, and the changes which 

 ensue. 



Foreign bodies enter the tusk in three ways — first, through 

 the free portion of the tusk ; secondly, through that part of 

 the organ which is contained in the socket ; and thirdly, from 

 above through the base of the pulp. 



First. When the ball hits the free portion of the tusk, if 

 it only penetrates to a certain depth of the ivory, no change 

 whatsoever can take place. Neither the cement nor the ivory 

 can be reproduced. In course of time the hole may be obli- 

 terated, the ball may be got rid of by wearing down of the 

 ivory, and the ivory under the hole may be strengthened by 

 the formation of new substance. AMien the ball is detained 

 by the ivory, but penetrates so far as to wound the pulp, the 

 latter ossifies around it, and the ossified portion sooner or later 

 becomes enveloped in new ivoiy. If the ball penetrates the 

 pulp, the latter ossifies round it, and becomes attached to 

 the hole in the ivory. If the tusk is growing rapidly, 

 and the nucleus of pulp-bone does not speedily adhere to 

 it, the ball wdl idtimately be situated above the hole. The 

 ball may also pass across the pulp, and become at last en- 

 veloped, along with its bony envelope, in the ivory of the 

 opposite wall. 



Second. In the second class of wounds, in which the ball 

 enters the pulp-cavity through the socket and side of the tusk, 

 the consequent changes seem to be the following : — First, 



