Ci Up. VII. 
THE RACES OF MAN. 
231 
' ? ould be extremely rash in most cases to attribute to 
convergence close similarity in many points of struc- 
lore i n beings which had once been widely different. 
form of a crystal is determined solely by the 
Molecular forces, and it is not surprising that dissimilar 
^stances should sometimes assume the same form ; 
c^t with organic beings we should bear in mind that 
^ le form of each depends on an infinitude of complex 
Nations, namely on the variations which have arisen, 
these being due to causes far too intricate to be followed 
°Ut, — on the nature of the variations which have been 
Preserved, and this depends on the surrounding physical 
c '°nditions, and in a still higher degree on the sur- 
r °unding organisms with which each has come into 
'''’’“petition, — and lastly, on inheritance (in itself a 
Uctuating element) from innumerable progenitors, all 
0 which have had their forms determined through 
^finally complex relations. It appears utterly incredible 
, lat two organisms, if differing in a marked manner, 
hould ever afterwards converge so closely as to lead 
0 a near approach to identity throughout their whole 
°j‘ganisation. In the case of the convergent races of pigs 
)°ve referred to, evidence of their descent from two pri- 
?Aive stocks is still plainly retained, according to Yon 
utliusius, in certain bones of their skulls. If the races 
’nan were descended, as supposed by some naturalists, 
°ta two or more distinct species, which had differed as 
^tach, or nearly as much, from each other, as the orang 
’Hers from the gorilla, it can hardly be doubted that 
Marked differences in the structure of certain bones would 
8tl H have been discoverable in man as he now exists. 
Although the existing races of man differ in many 
^spects, as in colour, hair, shape of skull, proportions 
the body, & c ., yet if their whole organisation be taken 
