STUDY OF VARIATIONS 
149 
individual differences from “ extended degrees of 
aberration from regular specific characters,” and he 
argues that the frequency of varieties is much 
greater among the simpler animals and plants. He 
cautiously admits: “ It is also highly probable that 
these new forms of difference may sometimes be 
permanent, and transmit their peculiarities of 
structure or appearance to their progeny, with 
or without the aid of those circumstances which 
originally induced these varieties.” 
Is not a sentence like the last almost evolution¬ 
ary ? It sounds so for the moment, but MacGillivray 
never seems to have entertained the idea that one 
species could by variation give rise to another. 
“ The boundaries of species,” he says, “ are absolutely 
fixed by Nature, one kind having no alliance with 
another.” 
In his brief review of the varieties occurring in 
animals and plants, MacGillivray expresses the 
conviction that “ some intention or design, in 
regard to varieties, pervades Nature ” :— 
“ Unless we admit that some particular office, 
or function, is set apart for very many varieties we 
meet with, I do not see how we are to account for 
their differences being so great. I conceive that in 
many instances, not only are the amounts of 
difference assumed as varieties as great as those 
between species, but that their uses are as peculiarly 
important in the great scheme of the universe as 
those of a vast number of species belonging to the 
same class or tribe as the varieties. It is not 
pretended, however, that these uses can be defined, 
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