MODERN SCIENCE. 149 



1788 1868. Boucher de Perthes discovered flint im- 

 plements and a HUMAN JAW in the drift of the river Somme 

 {1847), thereby causing a revolution in the views held hitherto 

 regarding the antiquity of man. He shattered at one blow 

 the erroneous ideas of mankind as regards the origin of man, 

 his place in creation, and his course of development. His 

 discovery was supplemented in 1853 by antiquarians rinding 

 the Swiss Lake dwellings, which are comparatively recent, 

 but which nevertheless added another evidence to the antiquity 

 of man. Other countless discoveries have extended our 

 knowledge on that point (see Broca and Agassiz). 



1791 1862. Knox (Robert) showed in his work, "The 

 Races of Man/' the PERSISTENCE of the Jewish, Celtic, and 

 German TYPES, and endeavoured to prove that distinctions 

 were immutable a theory which, though apparently sup- 

 ported by the evidence yielded by atavism (heredity), can 

 no longer be held in the face of the law of evolution. Knox's 

 facts are of much value, nevertheless, for they add another 

 set of proofs of the remote antiquity of man. For if man has 

 undergone no visible change within such a lengthy period as 

 the whole of the historical epoch, hundreds, perhaps thousands 

 of such periods must have been necessary for the production 

 of the many existing human varieties. 



17961850. Retzius gave a theory of CRANIOLOGY ac- 

 cording to which the whole human race would be divided 

 into two fundamental groups, founded upon the relation 

 between the antero-posterior diameter (length) and the 

 transverse diameter (breadth) of the skull the autochthons of 

 Europe (natives, aborigines), the stone-man being broad- 

 headed (brachycephalic), and the foreign population, the 

 bronze-man, being long-headed (dolichocephalic) ; but later 

 researches and discoveries have proved this easy method to 

 be insufficient for a correct classification of races. 



b. 1808. Pruner-Bey, after visiting Italy, Greece, Egypt, 

 Syria, Arabia, believed in the persistence of types in his- 

 torical times so long as there is no change of habitat ; founded 

 the differential characters of the human races upon their 

 physiological development; originated the ESTHONIAN 

 THEORY, according to which the Esthonians (who are brachy- 



