PREFACE. XI 



subject of cell -development, it clearly demonstrates the 

 necessity of reforming the older views of the character of 

 cellular structures, and, in showing the incontestible 

 evidence now existing as to the essentially primary nature 

 of the cell-contents or protoplasmic structures, at once 

 levels the new field of investigation in Plants, and affords 

 a basis for the clearing up of the analogies existing 

 between the Animal and Vegetable tissues. 



The Translator has confined himself to a careful 

 rendering of the text and a slight amplification of the refer- 

 ences, especially in cases where English translations exist 

 of the works quoted. To have revised, in accordance 

 with the present condition of knowledge, certain of the 

 speculations which are now a little out of date, would 

 have been interfering too far with the Author ; but the 

 sources are indicated whence the more recent facts may 

 be obtained. 



A. H. 



LONDON; September, 1853. 



