July 14, 1892] 



NATURE 



201 



the other two integuments ; it forms, at its apex, a drop of 

 sweet fluid which captures the pollen-grains carried by the 

 wind or possibly by insects. The outermost very thick integu- 

 ment becomes fleshy and bright- coloured, and is attractive to 

 herbivorous animals. In the division of the cells of the nucellus 

 at an early stage there is no evident predestination of one, as 

 there is in most Angiosperms, as the mother-cell of the embryo- 

 sac. In Gnetum. Gnevion and neglectum there are usually 

 two, three, or even more embryo-sacs which appear equally 

 capable of further development ; while in G. edule, and allied 

 forms, the author found only one. In the division of the con- 

 tents of the embryo-sac no diff^erentiation of a female apparatus 

 takes place in any of the species examined ; no corpuscles or 

 special ovum-cells are formed, and no antipodals ; but the proto- 

 plasm of the embryo-sac divides into a parietal layer of prim- 

 ordial cells, which appear to be altogether equivalent, and which 

 represent so many ovum-cells capable of fertilization. 



As the pollen-tube lengthens, its nucleus gives oflf a 

 smaller vegetative nucleus, probably soon after the en- 

 trance of the tube into the tissue of the nucellus. The 

 two nuclei remain very near one another ; the vegeta- 

 tive nucleus or prothallium cell remains unchanged, while 

 the generative nucleus increases greatly in size and divides 

 into two. In G. edule the apex of the pollen-tube has now 

 entered the apex of the embryo-sac ; while in G. neglectum it 

 appears to make a curve to avoid the apex of the sac, and be- 

 comes closely applied to its lower portion. After the pollen- 

 tube has entered the embryo-sac its vegetative nucleus disappears, 

 while each of the two generative nuclei surrounds itself with a 

 membrane of protoplasm, and the nucleus of each of these gene- 

 rative cells divides into four or eight. The actual coalescence 

 of the male and female nuclei was not observed ; but a number 

 of small nuclei were detected in the male generative cells, in 

 addition to its four (or eight) comparatively large male nuclei, 

 which the author regards as the nuclei of the primordial ovum- 

 cells which have wandered into the male generative cells ; and 

 the coalescence must take place within the male generative cell. 

 After the entrance of the pollen-tube, the parietal layer of proto- 

 ))lasm of the embryo-sac, in which the female primordial cells 

 are imbedded, breaks up into an endosperm tissue. 



The author regards Gnetum as representing a higher type of 

 the order GnetacecE than the other genera, Welwitschia and 

 Ephedra ; the fact that no endosperm is formed before ferliliza- 

 tim indicating an advance on other Gymnosperms. The pre- 

 sence of a large number of embryo-sacs, and the absence in 

 them of antipodils, may indicate some analogy with Casuarina. 

 The processes described above finally negative, in the opinion 

 of the author, the theory that the antipodals are a survival of 

 the female prothallium of Vascular Cryptogams; they appear, 

 rather, to be a degenerate and functionless female sexual appa- 

 ratus. According to this view, there are, in the embryo-sac of 

 Angiosperms, two female sexual apparatuses of similar origin, 

 the vegetative nuclei of which coalesce in each ; but one of the 

 two apparatuses is altogether abortive. Both the antipodals 

 and the egg-apparatus or embryonic vesicles consist of an arche- 

 gone reduced to a single cell. A. W. B. 



INTERNATIONAL CONGRESS OF EXPERI- 

 MENTAL PSYCHOLOGY. 



'"PHE second session of the above Congress will be held in 

 •^ London on Monday, August I, 1892, and the three follow- 

 ing days, under the presidency of Prof. H. Sidgwick. The 

 Congress will assemble in the rooms of University College, 

 Gower Street (kindly lent for the purpose), from 10 to i and 

 from 2 to 4.30. The following papers have been arranged for : — 



Prof. Delbceuf 



Dr. Alexander Bain 



Prof. M. Baldwin 

 Prof. Beaums 



Dr. BloRILLON 



Prof. Bernheim 



M. Binet 

 NO. 



" The Respective Spheres and the 

 Mutual Aids of Introspection 

 and Experiment in Psychology." 



" Suggestion and Will." 



" Psychological Questioning " (Des 

 questionnaires psychologiques). 



" The Applications of Hypnotic 

 Suggestion to Education." 



" The Psychical Character of Hys- 

 terical Amblyopia." 



" The Psychology of Insects." 



85, VOL. 46] 



, " The Appreciation of Time by 

 Somnambulists." 



" Laura Bridgman," 



"Principles of Psycho - Therapeu- 

 tics." 



" Theory of Colour- perception." 



" Investigations into the Muscular 

 Sense of the Blind." 



" Recent Researches in the Psy- 

 chology of the Skin." 



" The Visual Centre in the Cortex 

 of the Calcarine Fissure." 



"Inhibition of Presentations." 



"The Degree of Localization of 

 Movements and Correlative 

 Sensations." 



" Loss of Volitional Power (I'abou- 

 lie)." 



" A Law of Perception." 



"The Female Poisoner of Ain- 

 Fezza." 



" Experimental Inquiry into the re- 

 lation of Respiration to Atten- 

 tion." 



' ' The Direct and Associative 

 Factors in Judgments of 

 Esthetic Proportion." 



"The Sensibility of Women, Nor- 

 mal, Insane, and Criminal." 



"Investigations into the Parallel 

 Law of Fechner." 



"The Limits of Animal Intelli- 

 gence." 



"The Experimental Investigation 

 of Memory." 



"The Psycho-Physical Basis of 

 the Feelings." 



" The Experimental Induction of 

 Hallucinations." 



" The Characteristics and Con- 

 ditions of the Simplest Forms 

 of Belief." 

 I Prof. Preyer "The Origin of Numbers." 



" General Ideas." 



"The Future of Psychology." 



' ' The Anatomical and Physiological 

 Relations ofthe Frontal Lobes." 



"Experiments in Thought-Trans- 

 ference." 



" Binocular After-images." 



" Relation of Reaction-time to the 

 Breadth of Perception." 



"The Physiological Basis of 

 Rhythmic Speech." 



"On the Functional Attributes of 

 the Cerebral Cortex." 



The Meetings of the Congress will be General and Sectional. 

 It is provisionally arranged that the General Meetings will be 

 held on Monday or Thursday, and on the afternoons of Tuesday 

 and Wednesday ; and that the Sectional Meetings will be held 

 on Tuesday and Wednesday Mornings, and if necessary on 

 Thursday Morning. There will be two Sections at least : 

 Section A, Neurology and Psychophysics ; and Section B, 

 Hypnotism and Cognate Questions. Under Section A will fall, 

 for example, the papers of M. Binet, Profs. Henschen, Horsley, 

 Schafer, Waller, &c. ; under Section B will fall the papers of 

 Dr. Berillon, Profs. Bernheim, Delbceuf, Liegecis, Dr. Van 

 Eeden, Mr. F. W. H. Myers, and Mrs. Sidgwick. 



Reports will be given in by Profs. Sidgwick and James and 

 M. Marillier ofthe results of the census of hallucinations which 

 it was decided to carry out at the first Session of the Congress 

 (Paris, 1889). 



A Committee of Reception has been formed, which includes, 

 among others, the following names : — Dr. A. Bain, Dr. D. 

 Ferrier, Mr. F. Galton, Dr. Shadworth Hodgson, Prof. V. 

 Horsley, Dr. Hughlings Jackson, Dr. Charles Mercier, Prof. 

 Croom Robertson, Dr. G. J. Romanes, Mr. Herbert Spencer, 

 Mr. G. F. Stout, Dr. J. Ward, and Dr. de Watteville. 



The fee for attendance at the Congress is ten shillings, which 



Dr. Donaldsov ... 

 Dr. Van Eeden... 



Prof. Ebbinghaus 

 Dr. Goldscheider 



Prof. Stanley- Hall 

 Prof. Henschen... 



Prof. Heymans ... 

 Prof. V. Horsley 



Prof. Pierre Janet 



Prof. N. Lange 



Prof. Liegeois 



Prof. Lehmann 



Dr. Lightner-Witmer 



Prof. Lombroso 



Dr. Mendelssohn 

 Prof. Lloyd Morgan .., 

 Prof. G. E. Muller 

 Prof. Munsterberg 

 Mr. F. W. H. Myers ... 

 Dr. W. R. Newbold ... 



Prof. Preyer 

 Prof. Ribot 

 Prof. Richet 

 Prof. Schafer ... 



Mrs. Sidgwick ... 



Dr. E. B. Titchener 

 Prof. TscHiscH ... 



Dr. Verriest 



Dr. Waller 



