1038 OF THE HUMAN FAMILY, AND THEIR MUTUAL RELATIONS. 



among the offspring of the same parentage ; whilst more special modifications of 

 the ordinary type, such as the possession of six fingers on each hand and of six 

 toes on each foot, are of no unfrequent occurrence. Under ordinary circum- 

 stances, these modifications tend to disappear as often as they occur; the free 

 intermixture of those members of the race which possess them, with those which 

 depart less from the ordinary type, tending to merge them in the general 

 average. But there can be no reasonable doubt that, if the same kind of 

 segregation were practised among mankind which is adopted by the breeders 

 of animals for the purpose of perpetuating a particular variety if, for example, 

 the members of a six-fingered family were to intermarry exclusively with one 

 another any such variety would be permanently established as a new race. 

 Now if it be borne in mind, that the influence of a scanty population, in the 

 early ages of the human race, by isolating different families from each other, 

 and causing intermarriages among even the nearest relatives, would have been 

 precisely the same with that which is now exercised by the breeders of animals, 

 we see one reason why the varieties which then arose should have a much greater 

 tendency to self-perpetuation than those which now occasionally present them- 

 selves. And when, too, it is borne in mind, that the change in external condi- 

 tions induced by migration would thus operate not only upon the parents, but 

 upon the offspring, and would have a continual influence in so modifying the 

 constitution of the latter that the peculiarities thus acquired by them would be 

 transmitted in yet greater intensity to their progeny, there is no real difficulty 

 in accounting, upon the strictest physiological principles, for the widest depar- 

 tures from one common type of conformation which we encounter in our survey 

 of the different Races of Mankind. 1 



1046. Hence we are led to conclude, that, so far as regards their Anatomical 

 structure, there is no such difference among them as would justify to the Zoolo- 

 gist the assertion of their distinct origin. But, further, it can be shown that, 

 although the comparison of the structural characters of the Human races does 

 not furnish any positive evidence of their descent from a common stock, it 

 proves that even if their stocks were originally distinct, there could have been 

 no essential difference between them ; the descendants of any one such stock 

 being able to assume the characters of another. This, as already remarked, can 

 be proved by historical evidence in regard to a sufficient number of tribes, to 

 justify the same assertion with respect to others, whose languages, customs, 

 habits of thought, &c., have an affinity strong enough to warrant us in regard- 

 ing them as descendants of the same stock, whilst their physical conformation 

 is widely different. Each principal geographical area, that is so isolated from 

 others as to render it probable, a priori, that its population has extended from 

 one centre such as the Continent of Africa or America contains races of very 

 diversified physical characters, whose linguistic affinities make it almost certain 

 that they must have had a common descent ; and thus, in whatever mode the 

 types of the principal varieties are selected, they are found to be connected by 

 so gradual a series of intermediate or transitional forms, that it is impossible to 

 draw any such line of demarcation between them, as would be required by a 

 soundly-judging Naturalist for the boundary of distinct species. 



1047. A very important confirmation of this view is afforded by the essential 

 agreement which exists among the different Races of Men in regard to their 

 Physiological history; the variations which they present not being greater than 



1 For a masterly digest of the analogical evidence furnished by the changes known to 

 have been thus produced among domesticated animals, and of the modifications which 

 particular tribes of Men can be shown to have undergone within the historic period, see 

 Dr. Prichard's "Physical History of Mankind," and his "Natural History of Man;'' 

 see, also, the summary given by the Author in the " Cyclop, of Anat. and Physiol.," vol. 

 iv. pp. 1301-1339. 



