172 Dr. Schleiden on the Development of the 



21 9 . ,,, ^. . di2 -, ,1 , 3699 . 



— m^ Cf sm (2 i — ^J in ^ — and the term j— arises from 



1233 

 the combination of ---- tr^ee^ sin (f — fy) in the longitude 



(S X) with -— m* sin 2 t in --^ — . These are the most consider- 

 able, but it would evidently be impossible to employ with safety 

 any rule of approximation which did not embrace other terms. 

 In this and in other cases in the Lunar Theory it will be found 

 that coefficients, when formed correctly, are made up by the 

 addition of numerous small terms, which come from various 

 sources : hence the danger of attending only to the leading or 

 principal terms which may occur upon an incomplete exami- 

 nation, hence also the extreme practical difficulty of the pro- 

 blem in whatever manner it be approached. 



In the method which M. Plana has adopted, first, as is well 

 known, the mean longitude of the moon is obtained in terms 

 of the true longitude, and the true longitude is afterwards 

 found in terms of the mean longitude by reversion. But the 

 divergence of the numerical coefficients exists equally in the 

 former expression, and does not arise in the operation of re- 

 version. 



XXVI. Scrnie Observations on the Development of the Organic 



nation in Phcenogamous Plants. By Dr. M. J. Schleiden.* 



[With a Plate.] 



Nullo modo generationem explicasse judicare possum eos, qui ne 



ullam quidem partem, ne uUum attributum quidem corporis ex tra- 



ditis suis principiis explicuerunt, sed sermones saltem de ea re fecisse, 



utcunque doctos, vercs et elegantes. 



C. F. WoLFFy—Theo)ia Generationis. 



ALTHOUGH it must be granted that Linnjeus had a to- 

 lerably clear idea of the metamorphosis of plants, yet 

 the introduction of this doctrine and its reception into the 

 higher botany takes its date from Goethe. Long, however, 

 before Goethe, the ingenious C. F. Wolff had shown how 

 fruitful this idea could be rendered ; but his work was little 

 read by the botanists of the time, not at all understood, and 

 soon forgotten. Thus the science, to its prejudice, did not 

 gain possession of this doctrine through Wolff, in whose 

 hands it would probably have become so fertile, but through 

 Goethe, and owing to the manner in which it was introduced 



* From Wiegmann's Archivfur Zoologie, Part IV., Berlin, 1837. 

 [The Editors are indebted to the kindness of Dr. Wood, of Bristol, for 

 the translation of this paper.] 



