SCIENCE- GOSSIP. 



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the delicate equilibrium between the nucleohyalo- 

 plasni and the water molecule which is held in it 

 in a loose combination, after the manner of water 

 of constitution. It would seem probable that heat 

 would have somewhat the same effect ; but the 

 paragraph in question does not touch on this point. 

 On plasmolysing a cell the first effect is upon the 

 peripheral protoplasm, causing it to contract by 

 reason of extraction of water : it would appear 

 that the peripheral protoplasm also was deprived 

 of a certain amount of constitutional water, and 

 not only of that which keeps the whole mass turgid 

 by its existence in the spaces of its meshwork. 

 That this effect extends to the nucleus is interest- 

 ing from the point of view of nuclear structure, as 

 it shows that the nucleohyaloplasm is more or 

 less comparable with the endoplasm in ultimate 

 constitution. 



Tetrad Formation in Ovule of Larix. — 

 Professor Juel finds that, as in the case of the 

 microscope, the megaspore of Larix arises by a 

 tetrad division, the lowest of a series of four 

 megaspores germinating and producing a pro- 

 thallium, the other three presumably undergoing 

 atrophy or absorption. He also finds ("Journal 

 of Applied Microscopy," February 1901, p. 479) 

 that in the Asclepiadaceae and Cyperaceae the 

 pollen mother-cell gives rise to only one pollen- 

 grain. 



Investigating Vitality of Seeds by Electri- 

 city. — Dr. Waller employs as an indicator of 

 vitality of seeds the phenomenon of the " blaze- 

 current," that is, the galvanometrical token of an 

 explosive change locally excited in living matter, 

 and states (" Proc. Roy. Soc," April 1901, pp. 79- 

 92), that " if the after-currents aroused by single 

 induction currents in both directions are in the 

 same direction, the object investigated is alive," 

 and if the after-currents are in opposite directions 

 the object investigated is non-living. These 

 " after-currents " are analogous to those existing 

 in the intrapolar region of a nerve after passing a 

 polarising current through it. Dr. Waller finds 

 that beans not giving this so-called blaze-reaction 

 subsequently gave no signs of germination. Fresh 

 and vigorous seeds, on the other hand, manifested 

 a large blaze-response ("05 volt) and germinated 

 strongly. Older seeds manifested a smaller blaze 

 (■01 volt or less) and less active germination. 

 Still older seeds gave only 001 volt blaze, and 

 finally none at all. 



Movements of Particles in Protoplasm of 

 Spirogyra. — In peripheral protoplasm of cells of 

 a Spirogyra filament one may observe, just over 

 spots where pyrenoids occur in the chlorophyll 

 band, small particles, presumably of a protoplasmic 

 nature, in a state of rapid to-and-fro vibratory 

 movement. A high power must be employed 

 (magn. 800 diams.), and the light must be so 

 regulated as to give a good definition. After due 

 consideration I have come to the conclusion that 

 we must not identify these movements with the 

 so-called Brownian movement of small particles 

 that one sees so often in Desmids and other 

 Thallophyta. The movements of these particles in 

 Spirogyra are arrested on " fixing " the protoplasm, 

 and we know that the Brownian movement is a 

 purely physical phenomenon not necessarily de- 

 pendent upon the vitality of the protoplasm. The 

 evidence points strongly to the conclusion, which 

 must remain somewhat hypothetical till further 



investigations have been made, that these particles 

 are intimately connected with the nutrition of the 

 cell ; and the fact that their movements are more 

 or less confined to a limited area of the proto- 

 plasm, just over the pyrenoids, tends to show that 

 they may, like these bodies, be concerned in 

 starch formation. I have examined a number of 

 species of Spirogyra for this phenomenon, and find 

 that it is manifested most strongly in those species 

 that have relatively large pyrenoids in proportion 

 to the body of the cell. For the examination of 

 them careful focussing is required, and, as has been 

 before mentioned, judicious regulation of the light, 

 a sort of neutral tint being perhaps the best for 

 good definition. — H. A. H. 



Development of Bordered Pits in Pinus 

 SYLVESTRIS. — Longitudinal sections taken through 

 young stems of Pinus, and carefully stained with 

 methyl-green, will show the cambial layer, and 

 next this on the axial side young rudimentary 

 tracheides that have just arisen from the inner- 

 most cells of the cambium. These tracheides show 

 numerous areas, or "pits," in all stages of develop- 

 ment. They begin on the radial walls by the 

 formation of areas of thickening at certain spots 

 on either side of the middle lamella. These areas 

 increase in breadth, and in the final stages leave 

 only a small aperture on each side, these being 

 separated by the middle lamella, in the centre of 

 which a thickening of the "torus " has also arisen 

 in the form of a small disc-shaped structure. The 

 edges of the thickened " border " are during these 

 stages raised considerably above the surface of the 



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radial wall. The figures here shown will give an 

 idea of the several phases. An important point is 

 that the unthickened areas of the adjacent walls 

 enclosed by the borders in the rudimentary stages 

 later on become perforated ; the border, however, 

 may go on increasing in extent and thickness long 

 after this has happened. — H. A. II. 



Electromotive Phenomena in Leaves ex- 

 posed to Light. — Some interesting experiments 

 upon the electrical effect of light upon green 

 leaves have recently been carried out by Dr. 

 A. D. Waller ("Proc. Roy. Soc." lxvi. pp. 129- 

 137). He finds that in the leaves of Iris there 

 are present electromotive effects and after-effects 

 which amount to -02 volt in the positive or 

 negative direction, in response to illumination. 

 No results were obtained in petals, a fact which 



