THE VEGETABLE AND ANIMAL KINGDOMS. 147 



we are to look for an account of the external variations and 

 adaptations of animals. 



Here we are directly opposed by the prevalent doctrine 

 among naturalists, that species is intransible, and has so con- 

 tinued during all the time that scientific observation has 

 existed. 1 There is a certain variability, they admit, in 

 organisms, throughout successive generations, and for this 

 variability external conditions may account ; but such varia- 

 tions show a disposition to give way, when the original condi- 

 tions are resumed, or when the changed individual is mingled 

 in alliance with the original stock. There is therefore a fixed and 

 immutable character which we call species, and which can only 

 be traced to an origin differing as an event from the procedure 

 of nature in our own time. I trust to be able to show that this 

 doctrine is in such a condition with regard to facts, and has of 

 late been obliged by facts to make so many shifts in its 

 assumptions, that it is not entitled to the respect usually 

 assigned to it. 



The doctrine theoretically attaches the term species to every 

 organism which manifests the same peculiarities throughout a 

 series of generations. Practically, without waiting to watch 

 successive generations, or where, from the extinction of the 

 organism, this may be impossible, naturalists give the appella- 

 tion to every organism which presents a plurality of individuals 

 similarly marked. Very small peculiarities suffice. A parti- 

 cular spot on the wing of a butterfly constitutes it a distinct 

 species. The Golden Plover of Australia was so reckoned, and 

 got the name of Xanthocheilus, from only having a small 

 portion of yellow in the commissure of its bill. At the same 



1 Dr. Carpenter says, * ' Although the life of all organized beings com- 

 mences in the simplest and most general type of organic structure, so 

 that there is no perceptible distinction between their germs, yet we see 

 that each germ must have a certain capacity of development peculiar to 

 itself ; since it is a general law of organic development that like produces 

 like. However varied may be the series of forms through which the 

 parent passes, the offspring repeats these with the greatest exactness ; 

 and the whole scheme of development may be desci-ibed as one in which 

 the primordial cell is tending towards the attainment of the perfect form 

 and condition of its parent." I would venture to remark that, without 

 seeing the germ of a particular being maintain the tendency to the 

 parental form in the nidus of an animal specifically different from its 

 parent, \ve are not entitled to assume that it has " a certain capacity of 

 development peculiar to itself." Its capacity of development may be 

 quite indefinite, and only bound down to the attainment of the parental 

 form by being kept and nourished by the parent. 



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