MODERNBIOLOGY 393 



the truth, and this is still further emphasized in the eyes of a modern reader 

 by the fact that Schleiden uses a number of romantic-philosophical terms: 

 expressions such as " pofetiz^erte Zellen," "edlere Sdjte," and other similar 

 terms are clearly reminiscent of Goethe. What made this paper so original 

 is its insistence upon the independence of the cell; the plant is presented for 

 the first time as a community of cells, a " Poljpsfock," as it is expressly called, 

 and it was from this standpoint that future investigators started who with a 

 finer critical sense made use of the idea that Schleiden had produced. 



Schleiden' s text-book on botany 

 There is still one more important work from the hand of Schleiden that is 

 worthy of mention — his Grundxiige der ivissenschaftlkhen Botanik, which was 

 published in i84Z and at the time created an extraordinary sensation, criti- 

 cism being both favourable and unfavourable. Really in its way it is a 

 pioneering achievement; it implies a fundamental agreement both with the 

 purely systematic botanical training that had hitherto been in vogue, and 

 with the natural-philosophical conception of the phenomena of life. In a 

 lengthy "methodological introduction" Schleiden propounds his general 

 conception of nature, which represents the most interesting part of the work. 

 It shows that he held a well-thought-out philosophical view of nature, ac- 

 quired under the guidance of Jacob Friedrich Fries, professor of philosophy 

 at Jena, and one of the few thinkers who during the age of romantic specu- 

 lation maintained an interest in Kant's mode of thought. Following him, 

 Schleiden declares that the aim of natural science is "to relate all physical 

 theories to purely mathematical grounds of explanation." With this ideal of 

 exact research before him he tries to convert botany into a comparative in- 

 vestigation of life -forms and life-manifestations, with special reference to 

 the evolutional phenomena in the vegetable kingdom. As the cause of all 

 that happens in nature, both animate and inanimate, he assumes one and 

 the same "form-building force"; on the other hand, he strongly denies the 

 existence of any special life-force, and, as had often been done before, he 

 refers the growth of the crystal and the organ to the same category of phe- 

 nomena. In spite of this he is definitely opposed to the idea of spontaneous 

 generation of the higher animals and even rejects Meckel's "biogenetical 

 principles." In a purely philosophical connexion he maintains, with Kant, 

 the contrast between subject and object, and consequently also between 

 spiritual and material entities. Schelling's and Hegel's theories on the unity 

 of spirit and matter he dismisses with scorn. His "free-thinking" brought 

 him into dispute with the theologians; at that period the latter were monists, 

 following Hegel, while dualism was upheld by their opponents among the 

 biologists; in Haeckel's time, it will be remembered, just the contrary was 

 the case, which fact indicates that it was really the contrast between per- 

 sonalities that was the essential point 



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