6oo 



NA TURE 



[October 21, 1697 



that another experiment should be tried in winter time, with 

 clear and cold weather. He has also promised to direct to these 

 experiments the attention of the Parisian Committee for Scientific 

 Aeronautical Ascents. But it is likely that funds will be supplied 

 by Lyonnese scientific men and capitalists. The expense of this 

 ascent was borne by ]\I. Jacquemet, a country gentleman, whose 

 estate is in the vicinity of the Lyons Observatory. It is but 

 fair to add that these all-important investigations should not be 

 conducted with electrical kites, as used so cleverly in America for 

 obtaining the temperature of the air. W. de Fonvielle. 



BOTANY AT THE BRITISH ASSOCIATION. 

 'X'HE business of the Section was opened by the presentation 

 ■*- of reports (i) on the preservation of plants for exhibition, \ 

 and (2) the fertilisation of the Phreophycew. Since the interim 

 report on the preservation of plants (B. A. Report, 1896), the 1 

 Committee have continued their inquiries and investigations, and j 

 the result of their work has been largely to confirm the state- 

 ments contained in their previous report. They express the 

 opinion that alcohol on the whole yields the best results as a j 

 liquid medium for the preservation of specimens. Drying in l 

 sand, in cases where the specimens are not intended to be ( 

 handled, is recommended as a method by which admirable 

 results may be obtained. | 



The Committee appointed to conduct experiments on the I 

 fertilisation of the Phteophycere presented an interim report on 1 

 the favourable progress of the work. In the course of the | 

 meeting a cablegram was received by Prof. Farmer, the Chair- 

 man of the Committee, from Mr. J. L. Williams, of Bangor, 

 announcing the discovery of motile antherozoids in the genera j 

 Dictyota and Taonia. I 



Physiology. i 



A preliminary account of a new method of investigating fhe j 

 behaviour of stomata, by Francis Darwin, P\R. S. The inslru- I 

 nient used by the author in the present researches is a hygroscope 

 depending for its action on the extreme sensitiveness to watery 

 vapour of certain substances. The best material consists of thin 

 sheets of horn treated in a special manner, and known as 

 '•Chinese sensitive leaf." The other is what is used for the 

 toys described as "fortune-telling ladies," "magical fish," &c. 

 When either of these membranes is placed on a damp surface it 

 instantly curves with the concavity away from the source of 

 moisture. If one end of a strip of the material is fixed to the 

 lower surface of a block of cork, and is placed on the stomatal 

 face of a leaf, it is clear that only the free end can rise. It is 

 on this principle that the hygroscope is constructed, the angle 

 to which the hygroscope tongue rises being a rough indication 

 of the degree of transpiration. Thus on a leaf having stomata 

 only below, the index of the hygroscope remains at zero on the 

 upper surface of the leaf, while on the lower side it instantly 

 rises to an angle varying with the condition of the stomata. If 

 they are widely open the angle will be 30° or 40° to a horizontal 

 line ; if the stomata are closed the reading will be zero on both 

 surfaces of the leaf. The author is engaged in a general in- 

 vestigation of the behaviour of the stomata under varying 

 conditions. 



Some considerations upon the functions of stomata, by Prof. 

 C. E. Bessey. Prof. Bessey summarily reviewed the structure 

 of stomata, and discussed the needs of aquatic, terrestrial, and 

 aerial plants as to their getting of food, and the means by which 

 they resist the drying of their tissues. The author concludes 

 (i) that one of the functions of stomata is the admission of 

 carbon dioxide to the chlorophyll-bearing tissues of the plant, 

 for use in the formation of the carbohydrates. (2) That the loss 

 of water by terrestrial plants was originally hurtful, and is so 

 now in many cases. (3) That if plants have utilised this 

 constant phenomenon, it is for the supply of food matters of 

 secondary importance, as the salts in solution in the water of 

 the soil. 



Report upon some preliminary experiments with the Rontgen 

 rays on plants, by Prof. G. F. Atkinson. The experiments 

 were conducted for the purpose of testing the effect of the 

 Rontgen rays on plants exposed during a considerable period of 

 time. After a few preliminary experiments with leaves of 

 Caladiufii, flowers of Begonia, and various seedlings exposed 

 for one to ten hours, in which no perceptible injury resulted, a 

 run was made in which several seedlings were exposed for a 

 total of forty-five hours in a dark room. The plants behaved 



NO. 1460, VOL. 56] 



exactly as plants grown in a dark room. On removing the 

 seedlings from the dark room they all became slowly green, 

 but those which were uuder the influence of the Rontgen rays 

 recovered the green colour more slowly ; this suggests that the 

 rays may have a slightly injurious effect on the chloroplastids. 

 No other influence could be detected. Experiments were made 

 on the absorption of the Rontgen rays by plants. Species of 

 Mttcor, Bacteria, and Oscillatoria were exposed to the action of 

 the rays, but no influence was exerted on their growth or move- 

 ment. 



One morning session was devoted to a joint discussion with 

 Section I, on the chemistry and structure of the cell. Prof. 

 Meldola contributed an important paper on the rationale of 

 chemical synthesis, and Prof. J. R. Green gave an account of his 

 investigations on the existence of an alcohol-producing enzyme 

 in yeast. 



. Dr. Armstrong exhibited a series of diagrams, which showed 

 in a comparative manner the principal results of fifty years 

 experimenting on the growth of wheat at Rothainsted. 



Dr. Saunders, the Director of the Dominion Experimental 

 Farms, contributed a paper on the results of some experiments 

 in cross-fertilisation. He dealt chiefly with the efforts that had 

 been made to introduce fruits suitable for the climate of the 

 North-west Territories of Canada. Experiments were described 

 on hardy apples from Northern Russia, and other regions ; ant) 

 Dr. Saunders referred to two forms of Siberian crab-apples 

 from which promising crosses have been obtained. The author' 

 expressed the opinion that it will be possible in a few years to 

 supply the North-west Territories with apples capable of with- 

 standing the severe climate. 



On the structure of a hybrid fern and its bearings on hybridity 

 in general, by Prof. J. B. Farmer. This paper dealt with thc 

 characters, both macro- and micro-scopic, of Polypodiuni 

 Schneideri, a hybrid between P. aiireinn and P. vtilgare, var. 

 elegantissimtiin. The facts elicited from a study of this plant 

 were compared with those of analogous cases, and served as the 

 basis for a discussion as to the nature of hybrids and of 

 hybridisation. 



Thallophyta. 



Prof. Marshall Ward (President) contributed a paper on 

 Steretivi hirstituvi, a wood-destroying fungus. 



The author cultivated this fungus from the spores, on sterilised 

 wood blocks, and traced the action of the mycelium week by 

 week on the elements of the wood. He obtained spore-bearing 

 hymenia, and worked out the life-history very completely. 

 Ilartig, in his " Zersetzungserscheinungen des Holzes," ex- 

 amined the wood-destroying action of this fungus, but used 

 material growing in the open, and therefore not pure. Brefeld 

 attempted its culture, but failed to make it develop any fructi- 

 fication or spores. 



The fertile hymeniuin arises in about three to four months. 

 The author examined the development very thoroughly, and 

 referred to discrepancies in the existing descriptions. Tlie 

 details of its destruction of the wood were fully described ; the 

 fungus delignifies the inner layers of the walls of the wood- 

 elements, and in three months' cultures and upwards these turn 

 blue in chlor-zinc-iodine, and are shown by other reagents to 

 undergo alteration to cellulose-like bodies before their final 

 consumption by the fungus. 



On the mycelium of the witches' broom of Barberry caused 

 by Aicidiiij)i graveolens, by Prof. P. Magnus. The author of 

 the paper criticised the work of Dr. Eriksson on this parasitic 

 fungus. The intracellular mycelium, described by Eriksson in 

 the cambium cells of the host-plant, is regarded by Magnus as 

 the plasmolysed cell contents. The latter author finds that the 

 mycelium is always intercellular, and that it puts out branches 

 into the cells of the pith, medullary rays, and cortical parenchyma 

 of the host. 



The nucleus of the yeast plant, by Harold Wager. In Sac- 

 charovtyces cerevisecr. the nucleus can be easily demonstrated by 

 careful staining in hiematoxylin, Hartog's double stain of ni- 

 grosin and carmine, or by staining in aniline-water solution of 

 gentian violet. It appears to consist, in the majority of cases, 

 of a homogeneous substance, spherical in shape, placed between 

 the cell-wall and the vacuole. On the whole, it resembles more 

 than anything else the fragmenting nuclei in the older leaf- 

 cells of Ckara ; that is, it consists of deeply-stained granules 

 embedded in a slightly less stainable matrix. 



The process of budding in a yeast cell is accompanied by the 

 division of this nucleus into two. The division is a direct one, 



