136 



Scientific Intelligence. 



was afterwards appended to his Treatise on the Microscope, ed. 2, whi^h 

 is perhaps familiar to English readers in a translation made by Mr. Cur- 

 rey, and published by Highley of London. 



Schacht's statement immediately called out two notes, one by Hof- 

 meister, in the Flora for the 7th May, 1855 ; the other by Mohl, in the 

 Botanische Zeitung of the first of June; both are reproduced in the 

 number of Annates des Sciences JVaturelles, cited above. Both these ob- 

 servers, after repeated examinations of the preparation in question, deny, 

 in the most formal manner, that it shows what it was brought forward to 

 prove, and also deny that Schacht's figure of it is by any means a rigor- 

 ously exact representation. Hofmeister further explains how Deecke and 

 Schacht were, as he supposes, deceived by the appearance of the parts. 

 To this Deecke has rejoined, in Bot. Zeitung, xiii, p. 657, (republished, 

 with the figures, in Ann. Sci. Nat., vol. iv, [4th ser.] p. 58,) affirming the 

 correctness of the figures in question, and that the preparation proves the 

 embryo to originate from the pollen-tube. 



More recently, the able and indefatigable M. Tulasne, who made such 

 capital embryological researches six or seven years ago, has returned to 

 this subject ; and the results of a new series of investigations, relating to 

 several families of plants, were presented to the Academy of Sciences in 

 November last, and were published, the text in the Annates des Sciences 

 JVaturelles, 4th ser., vol. iv, p. 65, &c, and the twelve admirable plates 

 in later numbers of that volume. Their results entirely confirm M. Tu- 

 lasne in the views formerly sustained by him, namely, that the embryonal 

 vesicle, or in other words the first cell of the embryo, or of its suspensor, 

 does not make its appearance until the pollen-tube has reached the sur- 

 face of the embryo-sac, and that it originates in connexion with the inner 

 face of the embryo-sac, to which it adheres at a point opposite or near 

 that to which the extremity of the pollen-tube is applied externally. 

 This view, while it goes against the idea of preformed free vesicles, loose 

 in the sac, existing before anthesis or fecundation, and one of them, on 

 being fertilized, becoming the embryo (which is the view of Brongniart, 

 Mirbel, Amici, and especially of Hofmeister), and while it is strictly op- 

 posed to the Schleidenian hypothesis, — i. e. that the pollen-tube itself 

 becomes or produces the embryo, — at the same time offers a ready and 

 probably a true explanation of the facts adduced by Schleiden, Schacht, 

 <&c, indicating that what the latter have taken for the pollen-tube alone, 

 with its extremity transformed into the nascent embryo, may actually 

 consist of a suspensor originating within the sac, in juxtaposition with 

 the apex of the pollen-tube applied to it without. As the case now stands, 

 it appears most probable that to M. Tulasne belongs the honor of having 

 shown how the embryo of Phanerogamous plants originates. a. g. 



3. Sexual Reproduction in Algce. — Pringsheim's interesting paper up- 

 on the sexual fecundation and the germination of Algae, published in the 

 Proceedings of the Royal Academy of Sciences at Berlin, and briefly re- 

 ferred to in the number of this Journal for September last (p. 277), will be 

 found in a French version in the Annates des Sciences JVaturelles, ser. 4, 

 vol, iii, p. 363, tab. 15. That the " horns" of Vaucheria act as antheridia, 

 furnishing 'an therozoides' which by penetration fertilize the spore while 

 it is yet an amorphous mass, destitute of a cell-wall, is neatly shown. 



