PHYSIOLOGICAL BOTANY. 255 



ceeds. Some of the bundles may occasionally diverge 

 more considerably, as the author and Mirbel agree in 

 stating. I have no doubt that here also new vascular 

 bundles are formed between the old ones, which certainly 

 takes place as in Dicotyledonous trees. 



On Gaudichaud's Theory of the Merithals. By Pro- 

 fessor GUIS. MENEGHINI. Giornale Encyclop. Italiana, 

 vol. i, p. 17. This memoir, which was written as early 

 as 1843, at the time of the meeting of the Congress of 

 Philosophers at Lucca, must have contributed much to 

 draw attention to Gaudichaud's system. The author 

 sketched the elements of this system, which consists in 

 the unity of the axial system of the plant with the appen- 

 dicular system, the plant being regarded as composed of 

 phytons, intermediate forms, so to speak, between the 

 stem and leaf. The author admits this system as esta- 

 blished, endeavours to illustrate it by analogy with 

 animals, and considers that it must have the greatest 

 influence upon organography. It would have been more 

 desirable that the author, with the acuteness he possesses, 

 had investigated the whole theory more closely. He 

 would then have seen that the exposition of the system 

 rests upon an arbitrary assumption, which can only pro- 

 duce hypothetical results. That the radicle of Dicotyle- 

 donous seeds, of the Grasses and Cyperoidese, is the future 

 stem, has been known for thirty years ; but this is not 

 the case in other Monocotyledons. That all parts of an 

 organic being are originally one, no one can doubt, but 

 that the latter is directly developed into these parts, and 

 that the developed leaves, e. g., do not constitute the 

 entire stem, is evident on the slightest examination. The 

 author states his explanation of Gaudichaud's system to 

 be as follows : The fibres neither ascend nor descend ; 

 they are formed in the previously-existing cellular tissue, 

 by a gradual conversion of the cells of the parenchyma ; 

 the organization of the fibres is determined by the cur- 

 rents of the nutritive fluid and the descending fluids (sap) ; 



