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to the organization peculiar to certain families. Thus, therefore, the 

 continuity of the medullary radii, from one articulation to another, 

 may be considered one of the distinguishing characteristics of the 

 plants above mentioned. With the exception of the clematis and 

 aristolochice, which show it clearly at every age, this characteristic 

 can only be observed in the young stems. M. Brogniart then re- 

 marks, that the greater part of climbing plants have the stem almost 

 entirely composed of vessels of so large a bulk as to be visible to the 

 naked eye on the transversal section, which appears full of holes, like 

 a sieve. This characteristic, which is peculiar, not to the family, but 

 to the mode of growth of the plant, is considered by the author as a 

 necessary consequence of the small volume and great length of the 

 stem, which bears numerous leaves of a large size, because these 

 leaves occasion a profuse transpiration, and therefore require a struc- 

 ture of stem which will admit of a rapid passage of the sap, to supply 

 the loss occasioned by the transpiration. M. Brogniart then details 

 the remark which he has made on the internal organization of the 

 vine, the clematis, and the aristolochia, the most important of 

 which is the elliptical or oblong form of the section of the pith in 

 the last named family. The author also establishes that, in the 

 menispermee, the liber, or fibrous part of the bark, always remains 

 in the same state that it was in during the first year, not increasing 

 in any manner. Thus the cambium, which is interposed between 

 the wood and the bark, instead of being divided as usual into two 

 beds, the one of wood and the other of liber, is here entirely united 

 to the ligneous body. He has also remarked that, in the internal 

 structure of the stem of the menisperime, the ligneous body is divided 

 into several concentric layers, perfectly distinct from, and independent 

 of each other, each of which is the produce of several years, and that 

 the new beds are frequently entirely wanting on one side of the 

 stem, which is thus left naked. The pipera also offers some re- 

 markable characteristics, particularly, 1st, the formation of new ligne- 

 ous fascicules between those which primitively composed the ligneous 

 ring surrounding the pith, by which the diameter of the medullary 

 canal is increased, and 2ndly, the existence in the interior of the pith of 

 fibrous fascicules analogous to those of the ligneous body, the number 

 of which increases every year. M. Brogniart remarks, in conclusion, 

 that comparative anatomy ought to be the basis of the classification 

 of vegetables, as well as of that of animals ; and that the true charac- 

 teristics of the organization of a plant are rather to be found in the 

 body of the stem which produces the leaves and flowers, than in those 

 leaves and flowers which are but the offspring of, and dependent on 

 the stem. The reporters, although not disposed to believe that the 

 internal analysis of the organs can ever be of the same importance in 

 botany as it is in zoology, agree with the author that it must always 

 be a source of interesting and important investigation. The report 

 concluded with the highest eulogium on the talents and industry of 

 M. Brogniart, and the recommendation of the insertion of the essay 



