PliOBLEMS OF HUMAN DENTITION 131 



cation of such a process of progressive division. In all speci- 

 mens, the additional root, be it large or small, is wholly inde- 

 pendent of the normal posterior root. Even in its smallest de- 

 velopment it denotes its character as an additional element as 

 unmistakably as the so-called paramolar root does on the second 

 and third molar. Therefore I feel sure that this extra root of 

 the first lower molar in man is the manifestation of an element 

 in earlier phases of evolution wholly independent of the first 

 lower molar, as well as the paramolars. However this element 

 did not develop at the outer but at the inner side of the first 

 molar. And in critically observing the scheme in figure 21 it 

 becomes evident that in case of the coalescence of a rudimentary 

 P3 with the adjacent tooth, it must unite itself with the pos- 

 terior part of the lingual side of the first molar. Thus the topo- 

 graphical relationship between the lost P3 of man and his jMi 

 is in full accord with the significance of the supernumerary root 

 on our first molar, as described above. Therefore I wish to 

 denominate the extra root of this molar as 'radix premolarica.' 



THIRD PROBLEM: ON THE PROGRESSIVE VARIATIONS IN HUMAN 



DENTITION 



The third problem with which we shall occupy ourselves in 

 this essay, concerns the modifications w^hich will evolve in the 

 future in human denture. These changes are of different natures, 

 viz. : changes in the form of the teeth and changes in the number. 

 I shall confine myself to the discussion of the last kind of 

 variations. 



8e\'eral authors, jirojecting a classification of the anomalies 

 in the number of human teeth, have pointed out that two groups 

 of this kind are to be distinguished. A first group contains the 

 variations of an atavistic nature, whereas the second group con- 

 tains the variations of a progressive character. We must con- 

 sider as progressive variations all those by which the human den- 

 ture differs more widely from that of its forerunners and there- 

 fore also differs from the normal denture of the man of toda}'. 

 I agree with such a classification. But I do not believe that 

 every anomaly occurring in the human denture must necessarily 



