THE RECESSION OF THE JAWS 93 



third molar is larger than the second, which in turn 

 is larger than the first. In modern Man the first molar 

 is markedly larger than the second, which is again 

 markedly larger than the third. In the higher Apes the 

 third molar is the largest tooth of the molar series, and 

 it erupts before the canine. There is one other circum- 

 stance connected with the molar teeth that is worthy of 

 note. It is not extremely rare for a fourth molar tooth 

 to be developed in the roomy jaws of the skulls of ancient 

 races, and it is not at all uncommon for some diminished 

 remnant of this tooth to be present in modern primitive 

 Man. The presence of this fourth molar is all the more 

 remarkable, since its normal presence has to be sought 

 in a stock so apparently remote as the metatherian 

 (Marsupial) Mammals. 



Apart altogether from the anatomical development of 

 individual teeth, some light is thrown upon this question 

 by studying the quality of the teeth when developed. 

 We know that the teeth readily decay, and that caries in 

 modern civilized man affects the permanent set of the 

 adult and the temporary set of the child. Caries of the 

 milk teeth is so common as to be the rule in modern city 

 children, and few children shed their milk teeth without 

 decay having played some havoc among a set of teeth 

 the normal functional life of which is naturally brief. 

 But although the milk teeth were not intended to remain 

 in functional activity for more than ten years, they were 

 not meant to decay before or at that time. It is a striking 

 fact that, in the work of the Archaeological Survey of 

 Nubia (1907-08), no case of caries of the milk teeth 

 was found in the skull of any child living before the dawn 

 of the Christian era in Nubia. Among the hundreds of 

 cases examined, not one case of caries of the milk denti- 

 tion was discovered in the children of the early Egyptians. 

 The children of the more primitive living races rarely 

 show any traces of decay in the teeth of their infantile 

 set. In modern civilized children living a city life, not 



