1893.] NATURAL SCIENCES'OF PHILADELPHIA. 13 



I Entire arch hyperostosed, 3. 

 ( Entire arch absorbed, 4. 

 f Left side arch hyperostosed, 1. 

 ( Right side arch hyperos'osed, 0. 



( Left side arch absorbed, 2. 

 \ Right side arch absorbed, 4. 



Region of incisors hyperostosed (" beaked "), 6. 



Region of incisors " sheared, 5. 



f r Right and Left, 2. 



Region of canine and first bicuspid hyperostosed J Left, 1. 



(Right, 1. 



1 Right, 0. 



r> r j i- j j f Right and Left, 2. 



Region of second bicuspid and J j 7 ' , 



molars hyperostosed j i>- i! f -i 



n • r j i • -i j ( Right and Left, 0- 



Region of second bicuspid and I . ? , 



f Right and Left, 2 

 Region of canine and first bi-cuspid absorbed < Left, 



molars absorbed 1 T> . ,'. ,,' 



t Right, 2. 



r> • r j u- j j f Right and Left, 2. 



Region of second bicuspid and ] . ? 



molars " beaked " ) ,-.'. ,' „' 



L Right, 0. 



Symmetrical hyperostoses in alveolar arch in front of pterygoid process 8. 

 Incisive foramen in line of dental arch 8. 



It is noteworthy that from the entire series only four showed com- 

 plete absence of any secondary bone adaptation consequent upon 

 the loss of alveolar processes, and that all of these were from civil- 

 ized races, two ancient Egyptian and two Anglo-American. The 

 want of harmony between the secondary adaptations probably cor- 

 relates with the irregular rate at which the teeth are lost. Individ- 

 ual peculiarities in this regard are doubtless numerous. 



Dr. Allen assumed that the coarse food of savage and semi-savage 

 people caused the jaws even in an edentulous condition to be used 

 actively in the act of mastication, while the more carefully prepared 

 food suitable to the aged of civilized people enabled the jaws to have 

 comparative rest, and hence the mechanical conditions which pre- 

 determined the localization of new structures were not active. The 

 speaker concluded that the series of observations strengthens the 

 position taken that the same forces which differentiate the kind of 

 teeth operate in fashioning the shape of the jaws, even after the loss 

 of the teeth. 



Dr. C. N. Pierce remarked that the four superior arches, which 

 Doctor Allen has presented as being representatives of civilized 

 races, could not be accepted as indicating a uniform condition of 

 edentulous jaws at the present time. The crania collected from 

 civilized communities in the future will, in their edentulous jaws, 

 certainly show less irregularity in the individual alveolar ridges 

 than was present in the several specimens exhibited by Dr. 

 Allen, and in the absence or presence of a ridge would not 



