October 6, 1892] 



NATURE 



555 



' • On the cause of Physiological Action at a Distance, " by Prof. 

 L. Errera (Brussels). The author referred to Elfving's observation, 

 that sporangium- bearing filaments of Phycomyces nitens are at- 

 tracted by iron, zinc, aluminium, and various organic substances, 

 such attractions not being due to gravitation, light, moisture or 

 contact, but to physiological action at a distance, as Elfving 

 terms it. 



The author has made numerous experiments which tend to 

 show that the attraction is really hydrotropic, the filaments 

 being attracted by hygroscopic and repelled by non-hygroscopic 

 substances, for example : — 



Any modification of iron which lessens its capacity of rusting 

 at the same time diminishes its attraction on Phycomyces : thus, 

 polished steel scarcely attracts, and nickled steel does not do so 

 at all. 



China clay, which is very hygroscopic, attracts energetically, 

 while china exhibits no attraction. These experiments succeed 

 also in a saturated atmosphere, which shows that hydrotropism is 

 not due, as generally supposed, to differences in the hygrometric 

 state of the air. 



" Notes on the Morphology of the spore-bearing members in 

 the Vascular Cryptogams," by Prof. F. O. Bower. The 

 author explained by the help of a large series of diagrams 

 his views already laid before the Royal Society, as to the homo- 

 logy of the fertile frond of Ophioglossum with the sporangium 

 of Lycopodium. In support of the probability that the former 

 may have been derived from some such type as the latter, by a pro- 

 cess of partial sterilization of the sporogenous tissues, he adduced 

 facts relating to Isoetes and Lepidodendron, both of which show 

 a sterilization of parts of the potential sporogenous tissue in the 

 form of trabeculae in the sporangium. 



Mr. C. T. Druery sent in a communication, which was read 

 and remarked upon by Prof. Bower. It related to a new ex- 

 ample of apospory found in a young fern seedling, of which the 

 second frond bore upon its margin a number of prothalloid 

 growths. The occurrence of aposporous development at so 

 early a stage in the development of the sporophyte had not 

 hitherto been recorded. 



"On thearrangement of budsin Lemna Minor," by Miss Nina 

 F. Layard. The object of a series of observations made on 

 budding duckweeds, was to ascertain whether any fixed rule is 

 followed, both in the arrangement and order of production of 

 the buds. 



Prof. F. Schmitz read a paper on tubercles on the thallus of 

 Cystoclonium purpurascens and other red seaweeds. The 

 tubercles are constantly inhabited by bacteria, and appear to 

 arise in consequence of infection by these organisms. 



"CalamostachysBinneyana, Schimp.,"by T.Hick. The object 

 of the paper is to revise and extend our knowledge of the struc- 

 ture of this fossil fruit in the light of a number of preparations 

 which have not been previously described. The central part of the 

 axis, formerly described by Carruthers and Williamson as vas- 

 cular, the author finds to be cellular, thus removing the chief 

 ground for Williamson's reference of the spike to the Lycopo- 

 diaceae. Round the cellular pith there are (usually) three 

 primary vascular bundles, which are reduced to the condition of 

 those met with in Equisetum, and the young shoots of Catamites, 

 i.e. to as many carinal canals with annular and spiral vessels 

 adhering to the margin. 



As to the affinities, the conclusion arrived at is that the fruit 

 is that of some form of Calamites — as Carruthers maintained 

 long ago — and perhaps that of the type known as Arthropitys. 



" Myeloxylon from the Millstone Grit and Coal- Measures," by 

 Mr. A. C. Seward. Specimens of Myeloxylon (Brong.), 

 [Stenzelia (Gopp. ), Myelopteris (Ren.)] were described from a 

 limestone of Millstone Grit age in North Lancashire, their 

 minate structure being fairly well preserved, and showing 

 collateral bundles, gum canals (?), and the hypodermal tissues 

 characteristic of the genus. A much more perfect example from 

 the Binney collection was referred to, of coal-measure age, in 

 which not only the xylem but also the phloem elements had 

 been mineralised in an unusual state of perfection. 



It was pointed out that in the Binney specimen the position of 

 the Protoxylem on the Phloem side of the bundles was clearly 

 shown both in transverse and longitudinal sections. The affinities 

 of Myeloxylon with Cycads and Ferns were briefly discussed, and 

 the conclusion arrived at that this extinct genus, although differ- 

 ing in certain particulars both from Cycads and Ferns, should 

 be placed much nearer the former than the latter. 



SCIENTIFIC SERIALS. 



The American Meteorological Journal for September con- 

 tains the conclusion of " Objections to Faye's Theory of 

 Cyclones," by W. C. Moore. Only a few of the more essen- 

 tial characteristics of cyclonic storms have been considered, but 

 from these the author concludes that it is evident that the 

 generally accepted theory of convectional motion gives a more 

 satisfactory explanation of the various phenomena than the 

 theory advanced by M. Faye. — " Changes of Plane of the Mis- 

 sissippi River," by Prof. T. Russell. The author analyses a 

 report by Colonel C. R. Suter, of the Mississippi River Com- 

 mission relating to the improvement of the river and methods 

 of preventing overflow. — "Thunderstorms in New England 

 during the Year 1887," by R. de C. Ward. The difficulty of 

 predicting thunderstorms is shown by the fact that in New 

 England in 1887 the majority of storms occurred in the south- 

 eastern quadrant of cyclones, while in the previous year the 

 majority occurred in the southern or south-western quadrant. 

 Only 40 per cent, of the summer thunderstorms of 1887 

 occurred in the southern part of cyclonic storms, while in the 

 previous year the number was 70 per cent. — " Weather Fore- 

 casting at the Signal Office, June 30, 1891," by Prof. H. A. 

 Hazen. At this date the weather service was transferred to the 

 Agricultural Department, and the author has given the results 

 of his experience by laying down certain fundamental rules 

 which would be of service to a beginner in the work, as it has 

 sometimes been suggested that it would be almost impossible for 

 a forecaster to impart his knowledge to another. — " The Effect 

 of Topography upon Thunderstorms," by R. S. Tarr. The 

 author's observations have led him to believe that topography 

 has a decided effect upon the path of thunderstorms when they 

 are beginning. When, however, the storm has assumed more 

 than local proportions, topography has in all probability very 

 little effect upon its motion. 



SOCIETIES AND ACADEMIES. 

 Paris. 

 Academy of Sciences, Sept. 26. — M. Duchartre in the 

 chair. — On the white rainbow, by M. Mascart. A new mathe- 

 matical treatment of the subject shows that the diameter of 

 drops giving the most perfect achromatism is 29'l7/t. With 

 drops of 30^ the rainbow will appear the whiter, the more the 

 apparent diameter of the sun hides the excess of blue inter- 

 mediate between the achromatised points, as well as all the 

 supernumerary arcs, by the superposition of several systems of 

 fringes, so that there is only left an exterior border slightly 

 tinged with red. The same will apply to drops slightly different 

 in one sense or the other, but the achromatism persists longer if 

 the diameter diminishes. The observation of clouds and fogs 

 has shown that the diameter of the drops varies from 6 to lOOyit, 

 the last beginning to fall as rain. Thus the circumstances 

 favouring the production of white rainbows are of very fre- 

 quent occurrence. — Places of origin or emergence of the great 

 cholera epidemics, and particularly of the pandemic of 1846-49, 

 by M. J. D. Tholozan. From Dr. Arnott's communications to 

 the Physicomedical Society of Bombay, from the documents of 

 the Medical Committee of Bengal, and from the testimony of 

 Ferrier, who was travelling in Afghanistan at the time, it is 

 evident that the cholera epidemic which invaded Europe and 

 America in 1847, 1848, and 1849 originated in Bokhara, whence 

 it spread to Afghanistan and India, as well as westward. Bok- 

 hara, Samarkand, Balkh, and Kunduz were attacked at the end 

 of the summer of 1844, Herat and Kabul in October, Jellalabad 

 at the beginning, and Peshawur at the end of November. 

 In the following summer the epidemic proceeded steadily 

 eastwards into the "endemic area," reaching Jhelum and 

 Lahore in May, 1845, Meerut in August, and Delhi and Agra 

 in October, at the same time passing down the Indus to 

 Kurrachee, and westwards to Meshhed, whence it proceeded in 

 1846 to Asterabad, Teheran, Recht, and Baku. A similar 

 example of an eastward progress of cholera occurred in 1865, 

 when the great epidemic of Mecca, after having invaded 

 Mesopotamia and Transcaucasia, spread to Teheran, and took 

 the easterly route by Khorassan. The writer expresses his firm 

 conviction that the points of emergence of the choleraic 

 epidemics must be considered as their points of origin. The 

 idea that the different pandemic manifestations of cholera which 



NO. I 197, VOL. 46] 



