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30 EVOLUTIONS OF ORGANIZATION. 



One often hears final causes spoken of with a 

 contempt which is indeed only a revulsion from a 

 style of writing which will not now find many 

 admirers, in which adaptations were found by point- 

 ing out what extraordinary consequences would 

 follow some impossible alteration in nature, and 

 final were made to do the duty of efficient causes ; 

 but in the history of the vertebrate heart may be 

 seen a remarkable instance of the definite evolution 

 of a complex mechanism to perform a particular 

 kind of work. There is no reason to doubt that 

 here we have morphological evolution, and final 

 cause combined ; just as it is possible to imagine, 

 though we may have little experience of it, a build- 

 ing morphologically belonging to the Gothic order, 

 yet teleologically fitted for the wants of modern 

 science. 



It is a legitimate position to take up, that all the 

 evolutions of nature are definite, but that the series 

 of such evolutions is indefinite in number and 

 kind ; that individual evolutions, like other indi- 

 viduals, are finite, but form members of a larger 

 total. So, in the evolutions of organization we see 

 vortic units, the textural elements, receiving and 

 rejecting currents of material, while they maintain 

 during a finite life-time their individuality, and 

 these united into larger individuals subject to the 



