Great interest is represented by Wolff's perspicacious 

 discussion about the philosophical source of the predelinea- 

 tion hypothesis. He considered pre-established harmony to 

 be Leibnitz's idea. Censure of the idea of preformation is, 

 at the same time therefore, censure of Leibnitz's idealistic 

 proposition. It is important to be aware of this, because the 

 literature demonstrates the succession of the idea from 

 Leibnitz to K. F. Wolff, and through philosophy, physics 

 and botany from Leibnitz to Christian Wolff. If the influence 

 of Leibnitz on K. F. Wolff cannot be denied completely, then 

 Wolff's doctrine of essential power is not free from traces 

 of this influence. The independence of Wolff's philosophical 

 opinions must therefore not be overstated or overevaluated. 



From the early facts and considerations already mentioned 

 Wolff concluded the general laws of development, the most 

 important of which are formulated as follows: the appearance 

 of parts of the body and its organization are different 

 processes; first, the part is isolated, and then organized. 

 Essential for understanding Wolff's outlook is his confirma- 

 tion that "all parts of any organic body are formed by means 

 of this or that natural process" ($ 240) . He consequently 

 denied the role of any unknown principle in development. The 

 second chapter of his third part, summing up the investigation 

 of development, begins with a definition of this understanding. 

 Development is considered to be extremely general : Wolff 

 includes all changes, either appearance of new parts and 

 their formation by the extension of the substance of fluids 

 in particular, or simple growth and maintenance of existing 

 structures by means of nutrition C$ 241) . 



The different forms of development in plants and animals 

 represent manifestations of fundamental principles — the 

 essential power and ability of solidification of the nutri- 

 tional juices. Wolff again stresses the primacy of this 

 essential power. "The essential power," Wolff stated, 

 "together with the ability of solidification of the nutritional 

 juices, forms the acting principle of all development, either 

 in plants, or in animals" ($ 242). All other conditions or 

 principles of development Wolff called accessories; in some 

 way they promote the course of developmental process. Thus: 

 "Except for the essential power and the ability of the 

 developing substance to solidify, no other determining 



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