Ivory. 173 



decay of the milk-tushes, may have in some instances 

 been accompanied by incidents that gave rise to this 

 story. At the same time the probabihties are in favour 

 of its being true. Cuvier committed himself to the 

 statement that the tusks of the elephant have no attach- 

 ments to connect them with the pulp lodged in the 

 cavity at their base, from which the peculiar modification 

 of dentine, known as " ivory " is secreted ; ^ and hence, 

 by inference, that they would be devoid of sensation. 

 But independently of the fact that ivory is permeated 

 by tubes so fine that at their origin from the pulpy 

 cavity they do not exceed the -ib\~Q5 P'^^t of an inch in 

 diameter, Owen had the tusk and pulp of the great 

 elephant which died at the Zoological Gardens in 

 London in 1847 longitudinally divided, and found that, 

 " although the pulp could be easily detached from the 

 inner surface of the cavity, it was not Avithout a certain 

 resistance ; and when the edges of the co-adapted pulp 

 and tusk were examined by a strong lens, the filament- 

 ary processes from the outer surface of the former 

 could be seen stretching, as they were drawn from the 

 dentinal tubes, before they broke. These filaments are 

 so minute, he adds, that to the naked eye the detached 

 surface of the pulp seems to be entire ; and hence 

 Cuvier was deceived into supposing that there was no 

 organic connexion between the pulp and the ivory. But 

 if, as there seems no reason to doubt, these delicate 



' Annales du Museum, F. viii. 1805. Todd's Cyclop, of Anatomy, etc. vol. 

 p. 94, and Ossemens Fossilcs, quoted by iv. p. 929. 

 Owen, in the article on " Teeth," in 



