PROBLEMS OF HUMAN DENTITION 125 



As mentioned above the question whether our molars belong 

 to the first or the second dentition is answered by authors in 

 very different ways. Some say they belong to the first row, 

 others assert they are elements of the second row, and finally 

 a third group consider our molars a result of the coalescence of a 

 tooth of the first with one of the second row. I agree with none 

 of these opinions. In the first pages I have tried to make it 

 clear that the first molar of the catarrhine Primates, and there- 

 fore also of man, was originally a milk tooth, and in the present 

 section, I attempt to demonstrate that the second and third 

 molars belong to the second row, the corresponding elements of 

 the first row being the two paramolars. My conception is, I 

 admit, a somewhat more complicated one, than those of other 

 authors. But I can say of it, what scarcely may be said of the 

 other conceptions to the same degree, that my hypothesis is not 

 a mere theoretical one, being founded upon a great variety of 

 facts partly resulting from the examination of an extraordinarily 

 large amount of material. Therefore my hypothesis bears the 

 character of a conclusion and not that of a postulate. ]More- 

 over it demonstrates, at the same time, anomalies which cannot 

 be explained satisfactorily by other means. 



Before entering into the third problem which we intend to 

 discuss in this essay, \dz. : the future changes in human dentition, 

 we shall try to combine the results of investigations treated in 

 the foregoing sections. The nature of the subjects treated 

 in these sections facilitates a discussion of the same from a 

 common point of view; for both concerned a phase of the phylo- 

 genetical history of our dentition. In the first, in which I tried 

 to throw a new light upon the relationship between the dental 

 formula of platyrrhine and catarrhine Primates, particular 

 attention was drawn to the significance of our first molar. Several 

 points were elaborated to prove that in the ancestors of man 

 this tooth was a milk molar. In the second section I entered 

 into the problem of the nature of our second and third molars, 

 as belonging to either the first or the second dentition. I con- 

 sider the demonstration of a rudimentary region of our milk 

 dentition, extending buccally from our second and third molars 



