374 Reviews, and Notices respecting NCiV Books. 



donous or polycotyledonous embryo, and the same also is the case 

 with the vascular provision which it contains. We cannot be silent 

 on the merit of this sketch ; it is of an accuracy which is rigorously 

 demonstrated by the anatomy of the young plant. 



The vascular provision is composed of two sets of vessels : the 

 one is carried from the neck of the root to the bud ; the other 

 from the bud to the extremity of the root. The first raises as far 

 as the bud the raw sap which is there elaborated ; the second con- 

 ducts as far as the root a part of the elaborated sap. This, in the 

 dicolyledoneae, being carried along between the bark and the wood, 

 forms the new woody layers by its union with the utricles origi- 

 nating from the stem, and contributes in this manner to the growth 

 in diameter ; whilst the other, by extending itself forwards at the 

 centre, and terminating at the bud which transforms into orga- 

 nized matter a part of the sap come from the root, carries on the 

 longitudinal growth. It thence follows that the bud receives from 

 below nothing solid, nothing organized, that it creates altogether 

 the vessels which enter into its composition, and that it is these 

 same vessels, developed below, which are represented in the 

 woody layers of the stem and of the root, of which they constitute 

 the most important portion. And as to the utricles of the layers, 

 whether they are carried on from beneath upwards, or from the 

 centre to the circumference, they become organized on the spot 

 between the bark and the wood, and have nothing in common with 

 the bud. 



This series of phaenomena, which takes place in the natural state 

 of individuals, exists equally in those which are grafted. All the 

 wood of the stem and of the root placed below the graft is com- 

 posed of vessels emanating from the buds of the graft and of utri- 

 cles engendered by the subject. This proposition is the corner- 

 stone of the theory ; for if it were invalidated by observation, the 

 theory would fall to pieces. 



The double vascular apparatus and the phaenomena which result 

 from its presence, belong not to the dicolyledoneae alone; they are 

 also found in the monocotyledoneas ; but they there undergo the 

 niodifications required by the particular arrangement of the threads 

 of which the wood is composed. 



Such is in substance the doctrine which M. Gaudichaud pro- 

 fesses. If we consider attentively, it is, as we have already re- 

 marked, only that of Du Petit-Thouars and of Lindley; but 

 M. Gaudichaud has impressed upon it a character of generality 

 which it had not. To come to this result, he has brought together 

 a multitude of facts which, in whatever way they are interpreted, 

 will conduce powerfully to the progress of science. His opponents 

 it must be expected, will not fail to say that these facts, curious 

 and unexpected as they may be, might be explained quite as well 

 by their doctrine as by his. But notwithstanding this assertion, which 

 should not be received on the strength of a simple dictum, as coming 

 from persons who for a long time have formed another idea of the 

 phaenomenon of the growth of plants, all will agree, that by his 



