126 DEXTAL CYSTS. 



quently form the bony sockets^ thus placing each 

 papilla in a separate cavity. Concurrent with this 

 process, small growths take place upon the membrane 

 of the month, just as they dip into the papillary cavity 

 or follicle, which finally, by union with other growths, 

 form a lid which covers the papillae in a closed sac or 

 bag. Before the final closing of the follicle, a shght 

 folding inward of its lining membrane takes place. 

 This inward folding of the membrane of the primitive 

 groove is for the purpose of forming a new cavity — the 

 cavity of reserve — which furnishes a delicate mucous 

 membrane for the future formation of the permanent 

 teeth. The cavity in which the permanent tooth is 

 developed is a mere detachment from the lining of the 

 primitive groove, and in it a papilla is formed in the 

 same w^ay as that of a temporary tooth.' * 



" Now, I look on the formation of these tumors as 

 being due to some irregularity in this folding of the 

 lining membrane, by which the 'cavity of reserve' is 

 made up of several folds ; that these folds eventually 

 become separated, forming separate cavities of reserve, 

 and that a papilla similar to those of the natural teeth 

 is developed in each cavity. These irregular papillae 

 are converted into irregular teeth, which, for want of 

 space in the mouth, are forced into the antrum, and 

 may completely block it up, as well as the posterior 

 nasal opening. 



" I have classified them as cystic tumors, as at first 

 they are inclosed in sacs or cysts. They soon burst 

 through their investing membrane, however, and form 

 a large tumor, composed entirely of teeth, having a 



* Compare Professor Gondsir's theory with tliose advanced 

 by Messrs. Owen, Tomes, Chauveau, and others in the first 

 chapter. 



