MR GOODSIR ON MUSKET-BULLETS FOUND IN THE TUSKS OF THE ELEPHANT. 95 



looking those cases (one of which is given in the text of his author) in which ci- 

 catrices have been seen filling up the orifices produced by balls, explains satisfac- 

 torily enough those instances in which no such cicatrices exist, and concludes by 

 denying the power of the ivory to throw out ossific matter as asserted by BLU- 



MENBA.CH. 



The author of the Ossemens Fossiles, in his chapter on the structure, deve- 

 lopment, and diseases of the tusks of the elephant, after stating that grooves and 

 notches on the surfaces of the tusks never fill up, and only disappear from the 

 effects of friction, allows that musket-balls are found in ivory without any appa- 

 rent hole by which they could have entered. He does not believe that the holes 

 are filled up with ossific deposition as HALLER and BLUMENBACH supposed ; but 

 maintains that they are never obliterated. He states that the ivory on the out- 

 side of the ball is natural, and that it is only the bone surrounding it which is 

 irregular. The phenomena are to be explained, he says, by supposing the balls 

 to penetrate the very thin bases of tusks in young elephants, so as to enter the 

 pulps when still in a growing state. 



There appear, then, to be two circumstances, regarding which great doubts 

 still exist first, whether a shot-hole is ever closed up ; and, secondly, how this 

 is accomplished in a non-vascular substance like ivory. 



In proceeding to consider this subject, two facts must be borne in mind in 

 reference to a tusk. The first is, that the two substances of which it is composed, 

 ivory and cement, undergo no change of form or arrangement from vital action, 

 after they are once deposited ; the second, that it is an organ of double growth 

 it is endogenous as well as exogenous, the ivory being formed from without in- 

 wards, the cement from within outwards. 



As there are certain processes which invariably commence when a foreign 

 body passes through or lodges in the pulp, it will facilitate the conception of the 

 mode in which a bullet is inclosed if these be described first. 



Recent researches have proved that the regular ivory of teeth is formed by 

 the cells on the surface of the pulp becoming solid from the deposition of earthy 

 salts in their walls and cavities. It is evident from this that, when a portion of 

 the surface of the tusk-pulp is destroyed by the passage of a ball, the formation 

 of ivory at that spot must cease. But we know that the formation of irregu- 

 lar ivory commences, which indicates the existence of a healing process in the 

 pulp. The mode in which the wounded pulp heals, cannot be ascertained ; but 

 it is accomplished probably by effusion and subsequent absorption of blood, de- 

 position of lymph, and regeneration of the peculiar tissue of the pulp. So far 

 this process is conjectural, but the irregular ivory formed by the regenerated pulp 

 is the subject of observation. When, the ball passes quite across the pulp the 

 track heals, but does not necessarily ossify, except in the immediate neighbour- 

 hood of the ivory. 



