Academy of Sciences in Paris. 341 



applying his theory to the abortion of the carpillis, or parts of the 

 pistil, which he also imagines to be disposed spirally, and which 

 would be reduced to three or two, according as the outward or inward 

 part of the spiral is most disposed to increase in growth. The 

 reporter remarks, that these last considerations are too conjectural, 

 and must be regarded as more ingenious than solid ; and adds, that 

 the memoir has, in general, too great a tendency to hypothetical 

 views, although it is but justice to acknowledge that the conjec- 

 tures of M. Brogniart, which are, as usual, ingenious and interesting, 

 are not allowed to usurp the place of positive facts, an abundance of 

 which will be found to constitute the most solid part of the memoir. 

 In conclusion, the reporters recommended the memoir to the warm 

 approbation of the Academy. 



Development of the parts of Plants. On the 18th of July, M. 

 Cassini read a report on a memoir by M. Barbe, entitled ' Observa- 

 tions sur 1'impulsion qui provoque la saillie des germes radicaux 

 adventifs, et sur quelques autres points de Physique Vegetale.' The 

 object of the memoir, which will form part of a large work hereafter, 

 is to account for the fact previously observed by M. de Mirbel, that 

 the adventitious radical germs always develope themselves in a hori- 

 zontal direction ; or, to speak more correctly, in a perpendicular or 

 right- angular direction, with reference to the root from which they 

 spring. M. Barbe has given them the new name of eradians, be- 

 cause they are under the influence of a powerful radiating force ; and 

 concludes that the sprouting of the adventitious radical germs cannot 

 be produced by the ligneous fibre, because that could only act in its 

 own direction, which is always parallel to the axis, but that it is 

 operated on the points of the medullary radii, nearest to the liber or 

 inner bark ; and he is of opinion that the young roots are only ex- 

 pansions of these radii. In reply to the objection, that the roots are 

 produced on the substance of some leaves, (as for instance, the car- 

 damine pratensis.) M. Barbe states, that there are also medullary 

 radii in the leaves ; in proof of which, he cites the horizontal section 

 of the petiole of the leaf of the orange-tree, as a proof of there being 

 no connexion between the production of the adventitious roots and 

 the development of the foliaceous buds. M. Barbe mentions the 

 singular fact of a slip of willow having produced several roots, al- 

 ready arrived at a ligneous state, and even a new bed of wood and 

 bark interposed between those which existed at the time of plantation, 

 although the foliaceous buds were not at all developed. M. Barbe 

 has also particularly examined the functions of the small spots or 

 rents in the epidermis, which M. de Candolle calls lenticelles, and 

 supposes to be buds of the roots; whereas M. Barbe maintains that, 

 if they be not vegetable parasites of the class cryptogamia, (which, 

 however, he is disposed to think they are,) they are merely eruptions 

 of the feculent cellular tissue accumulated under the cuticle, and have 

 no relation whatever with the production of the radical germs. The 



