318 



gen der Konigl. Preuss. Akadeniie der Wissenschaften zu 



Berlin. Juli 1839 bis Juni 1840. — By the Academy. 

 Abhandlungen der Koniglichen Akademie der Wissenschaften zu 



Berlin. 1832. Thiels 3 and 4, and 1838.— 5j/ the Academy. 

 Flora Batava. No. 120. — By the King of Holland. 

 Annuaire Magnetique et Meteorologique du Corps des Ingenieurs 



des Mines de Russie. Annee 1838. Par A. F. KupfFer — 



By the Author. 



18 (h January 1841. 



The Right Hon. Lord GREENOCK, V.P. in the Chair. 



The following Communications were read : — 



1. On the Mode in which Musket-balls and other Foreign Bo- 

 dies become enclosed in the Ivory of the Tusk of the Ele- 

 phant. By John Goodsir, Esq. Communicated by Pro- 

 fessor Syme. 



The author commenced by stating, that " in all the specimens 

 he had examined, two circumstances were at once detected ; first. 

 That the balls were enclosed, not in the true ivory, but in an ab- 

 normal structure ; and secondly, that the holes by which the balls 

 entered were either partially or completely cicatrized in cases of 

 wound of the socket; which led him to suppose that, as the tusk 

 is an organ of double growth, the membrane of the follicle and 

 the pulp both play important parts in the process of enclosure, 

 and that there is no regeneration of true ivory, — an hypothesis 

 which was afterwards verified by observation. From a conside- 

 ration of the opinions of Camper, Blumenbach, Lawrence, and 

 Cuvier, it appeared that doubts are entertained as to the existence 

 of cicatrices after wounds of the tusk, and opinions held as to the 

 impossibility of the occurrence of such phenomena in a non-vas- 

 cular substance like ivory. To investigate this subject with suc- 

 cess, two principles must be kept in view : first, that a tusk is 

 formed from within outwards, as well as from without inwards ; 

 and secondly, that the ivory and cement are never changed by 

 vital action in form or substance, after their original deposition." 

 With these two principles, the author proceeded to explain the 

 healing of different wounds of the tusk, and the mode of enclosure 

 of balls and other foreign bodies, by describing in detail the de- 

 velopment and structure of the bony mass which appears in the 

 pulp after wounds. He stated, 1. That wounds of the surface of 

 the pulp are followed by ossification round the injury ; 2. That 

 the track of a ball across the pulp ossifies at the two extremities, 



