424 LECTURE XV. 



forehead so that nobody should kill him. This mark could 

 only have been intended for men^ for the wolf kills also marked 

 sheep. But where Cain could have obtained a wife^ or peopled 

 a city (at the time of Adam) must always remain a mystery^ 

 unless we assume that the history of Adam is no more than a 

 legend intended to prove the specific excellence of the Jewish 

 race. 



I merely allude to this to show that the only fact from which 

 we can start^ is that of the original dispersion of mankind upon 

 the earthy and the original difference of races spread over the 

 surface of the earth. However much we may indulge in theo- 

 logical speculations on the origin and differences of mankind, 

 however weighty jjroofs may be adduced for the original unity 

 of the human species^ this much is certain, that no historical, nor, 

 as we have shown, geological data can establish this dream of 

 unity. However far back our eye reaches, we find different 

 species of man spread over different parts of the globe. 



The geographical distribution of mankind corresponds more or 

 less with that of animals, though not within such narrow limits 

 as those drawn by Agassiz. Each race or species corresponds 

 to the general conditions of the countiy, chmate, and the sur- 

 rounding animal or vegetable world ; and the laws of distribu- 

 tion in general show the same shades which we find in the rest 

 of organic nature. As there are animals inhabiting a very 

 limited district which they never leave, so are there species of 

 mankind who are limited to a small space. Again, as there 

 are species of animals spread over large tracts, and enabled to 

 support the heat of the tropics as well as the cold temperature 

 of the north, so are there species of mankind presenting the 

 same power of adaptation to external media. Boudin has en- 

 deavoured to show, that of all known human races there is but 

 one, namely, the Jewish race, which can easily become accli- 

 matised in all the zones of both hemispheres, and can maintain 

 itself without intermixture with the native race, whilst all other 

 European races transjDorted from a temperate to a hot climate 

 would in the course of time become extinct, unless supplied by 

 immigration from the mother country, because the deaths 

 always exceed the births. Hence it follows that, excepting a 



