18 EVOLUTION BY ATROPHY 



(d) Teratology, which compares normal with 

 abnormal forms for the same purpose. 



In sociology these various systems of comparison 

 are only of a secondary value, owing to the great 

 variability of social forms, while the historical 

 method of investigation assumes a greater impor- 

 tance. In sociology, however, there are methods 

 analogous to the comparative methods of biology : 



(a) Archaeology corresponds to palaeontology. 



(b) Social morphology, by comparison of series 

 of institutions, makes up to a certain extent for 

 the absence of direct observation of their origin 

 and development. Thus, to use the phrase of 

 Bagehot, by studying the customs and institu- 

 tions of modern savages, the prehistoric living 

 may be made to throw light upon the pre- 

 historic dead. If an institution be found in full 

 operation among savages, of which a vestige still 

 exists among more civilized people, it may be 

 assumed that the vestige was at some time fully 

 functional among the latter. It must be borne 

 in mind, however, that in many instances such 

 vestiges are the result of imitation. Theodore 

 Reinach has shown that this applies in the case 

 of circumcision. 1 



This gravely weakens ^ the conclusions drawn by 

 Spencer from the survival of this custom among 



1 De quelques fails relatifs A Vhistoire de la circoncision chez Ics 

 peuples de la Syrie (Th. Reinach, L'Anthropologie, 1893, vol. iv., 

 pp. 28 and following). 



