128 R. F. SOGNNAES 



suggests that these canals represent a new and extremely rare type 

 of pathology occurring during life. In view of our present observa- 

 tions, however, it is significant to note that the two cases referred 

 to by Hopewell-Smith actually were observed in exhumed teeth, in 

 which we have seen that the condition, on the contrary, is extremely 

 common. 



Until similar canals are demonstrated in sections of freshly ex- 

 tracted teeth, it must, therefore, be concluded that we are dealing 

 with a condition which has not been proved to occur during life but 

 is very common after death. In further support of this contention is 

 an accidental, but important and apparently little known, observa- 

 tion made about a century ago by Wedl ( 1865 ) . He tells of having 

 asked an employee at a morgue to extract and save some teeth be- 

 fore disposing of the dead. By mistake the teeth were left in a glass 

 of polluted water for 10 days before being prepared for histologic 

 examination. Upon sectioning, Wedl discovered a number of pre- 

 viously undescribed canals penetrating into the dentin and cemen- 

 tum from the outside surface. When Wedl's drawings recently came 

 to my attention and were compared with the photographs of the 

 present study, especially those in Figs. 21 and 22, the similarity be- 

 came immediatelv apparent. This characteristic postmortem dental 

 destruction, as well as the canals which Roux (1887), twenty years 

 after Wedl's report, observed in exhumed bone, may therefore more 

 appropriately be termed "Wedl's canals," as suggested in a historical 

 note by Schaffer (1895). 



The external canals observed by Wedl were obviously produced 

 under somewhat unusual circumstances, immediately after death 

 and in the course of less than 2 weeks. It is not known whether the 

 canals observed in our exhumed specimens were similarly produced 

 shortly after burial, before the process of putrefaction set in, or later. 

 Some of our observations suggest that much of the postmortem de- 

 struction must have taken place a longer time after burial. In the 

 first place, it was noted that the internal canals occurred with great- 

 est frequency. This means that the pulp, as well as the periodontal 

 membrane and other soft structures, must first have undergone pro- 

 teolysis and that many of the teeth must have been severed from 

 the jaw before becoming accessible to the agents responsible for the 



