870 



early anatomical essays of the poet Goethe ; and it may confidently 

 be stated that the most characteristic feature in the recent progress 

 of anatomical science, has been the establishment of the principle, as 

 applicable to the vertebrated classes, in the works, " On the Arche- 

 type of the Vertebrate Skeleton," and " On the Nature of Limbs," by 

 the distinguished author of the memoir already alluded to, On the 

 Homologies of the Skeleton of the Chelonian Reptiles. 



Several points of interest occur in the progress of Physiological 

 Botany during the past year. 



Professor Schleiden, in the new edition of the first volume of his 

 ** Grundziige der Botanik," modifies the opinions he formerly held on 

 the subject of cell-formation. He now admits with Nageli, that the 

 original coating formed around the cytoblast is not the cell- membrane, 

 but a layer of protoplasm, the nitrogenous substance from which a 

 layer of cellulose is subsequently secreted. He also admits the di- 

 vision of cells by the separation of the nitrogenous lining of IVIohrs 

 * primordial utricle,' into ..two halves, between which a cellulose 

 membrane is secreted. These views are very different from those 

 propounded in his earlier treatise on Phytogenesis. 



Count Suminski's remarkable observations on the reproduction of 

 Ferns have attracted much attention. The process of generation 

 described by that author has been questioned in an essay by Dr. 

 Albert Wigand, who has minutely investigated the subject. Our 

 authors have adopted Suminski's views, but apparent^ without 

 having made original observations. 



M. G. Thuret has described organs similar to the supposed an- 

 theridia of Ferns, as found by him. on germinating Equiseta. 



M. W. Hofmeister has published an elaborately illustrated memoir 

 on the Origin of the Embryo of the Phanerogamia ; he concurs in the 

 views of Amici and Mohl. Mr. Henfrey has communicated to the 

 Linnsean Society a series of observations; by which he arrived at 

 similar results ; but Professor Schleiden still maintains the doctrine 

 that the apex of the pollen-tube becomes the embryo, and Schacht, 

 who has obtained the prize offered by the Dutch Institute for an 

 Essay on Vegetable Embryology, advocates the same opinion. On 

 the other hand, Professor Unger has published an essay on the de- 

 velopment of the embryo, in which he directly opposes Prof. Schleiden. 

 Various other memoirs of interest, on the subject of de^'elopment of 

 special structures or of the organs of particular tribes of plants, have 

 appeared in the Botanical Journals, chiefly from German authors. 



The Discourse on Parthenogenesis, by Prof. Owen, contains points 

 of much interest to the physiological botanist. 



I have given a very slight and imperfect outline of some of the 

 recent contributions to the progress of human knowledge ; of Che- 

 mistry and of Geology I have said nothing : it would have been im- 

 possible to have entered upon so wide a field without extending this 

 Address far beyond all reasonable limits. Enough, perhaps, has been 

 said to show that discovery is progressing in a continually accele- 

 rated ratio ; and as each new discovery, as a new example of design, 

 tends continually to keep ever present to our minds the great truth 



