106 



nipper only ; but even in that instance, a white mark 

 indicates that the cavity is merely filled up by crusta 

 petrosa, the enamelled lining not being yet worn 

 out. The alteration in the form and magnitude of 

 the infundibula cannot, if the accompanying wood- 

 cut be compared with those which have preceded it, 

 fail to strike the reader ; indeed these changes, aided 

 by the worn appearance of tables of the shell teeth, 

 are now the principal guides when judging of the 

 age by the mouth. 



52. After the eighth year, there is no certainty 

 in any opinion drawn from the teeth. A guess may 

 be hazarded, and very often that guess will prove 

 correct, but at the same time it should be received 

 only as a conjecture. The chance of naming the 

 age decreases as the number of years increase. After 

 the twelfth, the probability of hitting the exact year 



