320 GEOGRAPHICAL BOTANY. 



The excellent work of A. Wagner, on the ' Geographi- 

 cal Distribution of the Mammalia/ (Abhandlungen der 

 mathem. physik. Klasse der Bairischen Akad. Bd. iv), 

 which belongs to an allied province, but was not designed 

 without regard to the geographical relations of other 

 organisms, must not be passed over here without notice. 

 The question of the original native country of the various 

 organisms is acutely investigated by the author, and it is 

 found that the distribution of animals, as of plants, can- 

 not be satisfactorily explained by the climatic and local 

 conditions of their existence, but that the most rigid facts, 

 together with the physical relations at present in existence, 

 point to other, perhaps historical causes, with which we 

 are at present unacquainted, and which the author con- 

 siders as the effects of a general order of the creation, 

 which ought, however, rather to be kept in view by us as 

 objects worthy of future investigation. From the observa- 

 tions, in Belgium, upon the Periodical Phenomena of 

 Vegetation, published by Quetelet, and mentioned in the 

 previous Yearly tteport, the following brief extract, con- 

 taining the period of the appearance and fall of the leaves, 

 in the year 1841, of some generally diffused woody plants, 

 may be of use in the determination of the Phyto-isotherms 

 of Northern Europe ; and for this purpose it will be con- 

 joined with some observations simultaneously made by 

 Hartmann, in Gefle (60 N. 1.) (Bot. Notis. 1842.) 



