Imagens das páginas

exhaustible problem of growth, and, lastly, the conditions which determine or which prevent the entrance of the spermatozoon into the egg.

In Prof. Loeb's book, which bears the title set at the head of this short article, there is a wellknown chapter on heliotropism, that is to say on the tendency of plants to turn towards the light, and on other kindred phenomena manifested both in plants and animals; for the polypes of a hydroid colony such as Eudendrium, or the tube-dwelling worms such as Serpula or Spirographis, also bend towards the light, and if they be illuminated by a single beam they grow steadily in the direction of its rays. It is characteristic of the plant (or rather of the green plant) that it represents a peculiar type of machine which is capable of turning radiant energy into chemical energy, and so ultimately into mechanical work; and in the case of the plant, "the permanency of this kind of machine is guaranteed by the presence of an automatic arrangement, whereby their stems turn towards the light." So Loeb is inclined to read into this phenomenon what we might call a modified teleology, such indeed as, in one form or another, refuses to be kept out even of our most modern biological speculations.

In the chapter already alluded to, published some nine years ago, our knowledge was said to be very scanty as to the relative heliotropic efficiency of the various parts of the spectrum, little more being known than that the more refractive rays, the green, the blue, and the violet, were more effective than the yellow and the red. "There exists thus, apparently," said Prof. Loeb, "a division of labour, the longer light-waves accelerating assimilation, and the shorter waves accelerating heliotropism;"-just (we might say) as there is obviously a 'division of labour" between the rays which illuminate and those which

warm us.

Two of Prof. Loeb's recent papers (by Dr. H. Wasteneys and himself) (Pr. Nat. Acad. of Science, January, 1915, and Science, February 26, 1915) are devoted to the question of the identity of heliotropism in plants and animals, and thereby to an inquiry into the particular wave-lengths of light to which, in one case or another, they are most sensitive. Instead of exposing the organisms to the solar spectrum itself, as had been done in earlier and simpler experiments, the writers (using a carbon arc spectrum) allowed the light from particular portions of it to pass through narrow slits, and then reflected it in a monochromatic beam upon the subject of their experiments. They soon arrived at the simple but very remarkable result that there are two particular regions of the spectrum the rays of which are especially effective in causing organisms to turn, or to congregate, towards them; these regions lie (1) in the blue, in the neighbourhood of a wave-length of 477 μμ, and (2) in the yellowish-green, in the region of λ=534 μμ; and these two wave-lengths affect different organisms, with no very evident relation to the nature of these latter. Thus the blue rays (of 477 μμ) attract the infusorian Euglena, the

hydroid Eudendrium, and the seedlings of oats; while the yellowish-green rays (of 534 μu) in turn affect the protozoon Chlamydomonas, the little water-flea Daphnia, and the larvæ of barnacles.

These facts add a quality of precision to many older and vaguer observations, for instance, to Paul Bert's discovery (in 1869) that Daphnia swims towards the light in all parts of the visible spectrum, but most rapidly in the yellow or the green. The particular wave-length of 534 is especially remarkable, because it coincides with a determination by Trendelenberg that the visual purple of the rabbit's eye (which is not affected by red and very little by yellow light) is bleached most rapidly by light the wave-length of which is 536 up. It would seem, according to Loeb, that among the lower organisms we have to deal with two separate photosensitive substances, which determine their heliotropic reactions; that these are distributed without regard to the systematic boundaries, even between plants and animals; and that one of the two, occurring even among very lowly organisms, has characters similar to, and is perhaps identical with, the visual purple of the highest type of eye.

In another paper (Science, November 6, 1914), still dealing with the effects of light, Prof. Loeb relates some remarkable observations on the action of ultra-violet rays upon unfertilised eggs, adding by these new experiments a curious detail to the many facts regarding artificial fertilisation, by chemical or physical means, which we associate with his name as their prime discoverer. On the ground that ultra-violet rays are known to have a sterilising effect, that is to say to be capable agents in the destruction of cell-life, and that, according to Loeb's own experiments, the very substances which induce "cytolysis" in the living cell are also capable (under proper conditions) of producing artificial parthenogenesis, Loeb thought it likely that these rays would also prove to be effective stimuli, under the appropriate conditions, of parthenogenetic development. He exposed the unfertilised eggs of a sea-urchin for ten minutes to the light of a quartz mercury arc lamp, and found that the majority of the eggs formed "fertilisation membranes "; when kept cool they further proceeded to segment, but ere long perished; an addition of hypertonic sea-water, however, enabled them to develop into larvæ, though few advanced beyond the gastrula stage. It was remarkable that a cover-glass, o'r mm. thick, was sufficient to prevent all action on the part of the light, a fact which bears closely on the wave-length of the rays which produced the action.

The discovery here mentioned is certainly interesting as a specific case of the effect of radiant energy on living protoplasm; but its precise degree of interest turns largely on the importance which we may attach to the formation of a surface-membrane as an essential preliminary to the development of the egg. According to Loeb this phenomenon is of supreme importance; for the question why an unfertilised egg cannot grow, and why a fertilised egg can grow and divide, depends, according to

him, entirely on the condition of the surface layer of the egg; the nature of this cortical layer determines whether the egg be in an active or a passive phase, and the essential factor is a change in the rate of oxidation, to which the condition of the cortical layer directly leads. "The forces which induce the egg to develop are, therefore, localised at the surface of the cell." This is a somewhat hard saying, but in Prof. Loeb's hands it leads to many suggestive and stimulating reflections. The whole subject is discussed in his book on "Artificial Parthenogenesis, etc." (1913), and in a paper now before us, on the Stimulation of Growth (Science, May 14, 1915).



SIR SANDFORD FLEMING. HE death of Sir Sandford Fleming on July 22nd at eighty-eight years of age has deprived the world not only of one of its greatest engineers, whose constructive works revolutionised trade and commerce by providing increased facilities for intercouse, but also of one who in various ways proved himself a pioneer, advocating and supporting measures the importance of which had not yet penetrated the public mind. He will be longest remembered for his work on the Canadian Pacific Railway and for his successful advocacy of a cable across the Pacific, which has proved of so much value to the commercial world. But in smaller matters he exerted himself not less strenuously and usefully. In new country where material interests are many and pressing, he early saw the necessity of upholding pure science for the encouragement it could give to arts and industry, and with this view, so far back as 1849, he promoted the foundation of the Canadian Institute, which after demonstrating its usefulness in various directions, was recently incorporated under a Royal Charter.


Not less farseeing and useful was Sir Sandford Fleming's proposal in 1879 to legalise a universal day, beginning at mean noon of Greenwich time, the hours being counted continuously from o h. to 24 h. Five years later this suggestion bore fruit at the conference at Washington, summoned to consider more uniform methods of reckoning time, and at which it was resolved to adopt a single prime meridian for all nations in place of the initial meridians, favoured as this mode of reckoning was by international jealousies. At this conference Sir Sandford Fleming represented Canada, and it was there that the zone system of reckoning with which his name has been intimately connected was first ventilated. venience of adopting a standard time differing by an exact number of hours from universal time was insisted upon, and it was shown that it was not necessary, as maintained at a previous conference at Rome, to retain exact local time side by side with universal time. We have not yet achieved the arduous task of counting the hours consecutively from o to 24 h. as recommended, but the method is so eminently desirable in civil affairs as

The con

being thoroughly explicit and rendering unneces sary the distinguishing suffix a.m. or p.m., that we may hope the practical advantages will become apparent to the public as they were to the eminent engineer whose death we regretfully



THE Société Helvétique des Sciences Naturelles will hold, at Geneva, on September 12-15, its ninety-seventh annual session, which will coincide with the hundredth anniversary of its foundation. On account of the disturbed conditions existing at the present time, the council of the society has decided to celebrate this anniversary very quietly, and not to send the usual invitations to foreign scientific societies, or to men of science residing outside Switzerland.

THE Toronto correspondent of the Times announces that the Commission appointed by the Ontario Government to investigate the production and shipment of nickel in relation to the conditions created by the war consists of Mr. G. T. Holloway, of London (chairman); Prof. W. G. Miller, provincial geologist; Mr. McGregor Young, K.C., Toronto; and Mr. T. W. Gibson, Deputy-Minister of Mines. It is understood that in the course of its investigation the Commission will visit England and Norway and the New Caledonia mines in the South Seas. The Commission will also consider if nickel can be successfully refined in Canada. The importance of nickel as a munition metal was described by Prof. Carpenter in an article in NATURE of July 15 (p. 539).

A NOTABLE instance of the advantage to the State of calling in the aid of science in relation to difficult problems bearing directly on the well-being of our fighting forces is illustrated in the exhibit recently installed in the central hall of the Natural History Museum showing the work done in connection with an investigation undertaken jointly by the War Office and the Museum to determine the origin of damage to army biscuit by insect pests, and to prevent or minimise such infestation. Attention was directed to the matter some time ago by the fact that ration biscuits exported to the colonies became after a time quite unfit for consumption, owing to the ravages of certain moths and beetles-this was specially noted in South Africa, Ceylon, Gibraltar, Malta, Mauritius, and the Sudan. In answer to an application from the War Office, the trustees of the British Museum placed at the disposal of the military authorities for the purpose of the inquiry the services of Mr. J. Hartley Durrant, the expert in charge of the collection of microlepidoptera at South Kensington. It is most satisfactory to learn that these researches, which have been carried out jointly by the two departments concerned, extending over a period of three years, have ensured the protection of army biscuit from the possibility of such attacks by insects in the future. The insects met with during the inquiry were all widely distributed species the range of which has doubtless been greatly extended by commerce.

[merged small][ocr errors]

It is with regret that we record the death of F. P. J. Guéguen, late professor of botany in the School of Agriculture at Grignon. Prof. Guéguen was born at Loudéac, in Brittany, in 1872, and, having trained at the Ecole Supérieure de Pharmacie, became a hospital pharmacist in 1895. In 1899 he gained the title of doctor of pharmacy, his thesis being an account of researches on the mycelia present in pharmaceutical solutions. He afterwards devoted himself chiefly to cryptogamic botany, became assistant professor in the Ecole de Pharmacie in 1904, and for the last few years of his life occupied the chair of botany in the School of Agriculture at Grignon. Prof. Guéguen published numerous papers dealing chiefly with cryptogamic botany.

THE death of Sir James Murray, on July 26, removes a well-known figure from Oxford society. For more than thirty years his face and form had been among the most familiar sights in the University. His courteous manners and address, and his air of grave distinction, attracted the notice even of strangers, but to those who knew him intimately he was one of the most delightful of associates. Learned, but no pedant, keenly interested in all departments of mental activity, possessed of a wide acquaintance with science and literature, and equipped with knowledge, probably unequalled, of his own special branch of inquiry, he was always ready to impart information from the immense stores of his erudition. He had the gift of interesting others in his own subject without forcing it upon them or wearying them with over-minute details. His enthusiasm in his great work of the New English Dictionary, though evident to all who knew him, was held within due bounds by a plentiful endowment of common sense and a certain good-humoured shrewdness of nature, which was no doubt attributable to his northern origin. His conscientiousness was extreme. He spared no pains in ensuring the utmost accuracy of definition for the technical terms in the dictionary, taking every opportunity of consulting those best qualified to advise on such subjects. But he was no mere compiler, and his own mathematical and scientific knowledge was employed with excellent results. Though in his bearing the pink of courtesy, he could be trenchant in literary or philological criticism. Amusing stories have been current of the way in which some of his comments on other lexicographers have been toned down for publication by his assistants. His death at the age of seventy-eight has disappointed the hopes of those who looked forward to see him finish the great work now so near completion.

By the death of Dr. Alexander Stewart, principal of St. Mary's College, St. Andrews, which occurred somewhat suddenly on July 21, science has lost a genial friend and supporter, who, throughout his twenty-one years of office as principal, was ever ready in a quiet and judicious way to champion her cause. As an old and distinguished student of St. Andrews, for he was first bursar in 1864, and, later, Lord Rector's prizeman, and a graduate of the University, he took a deep interest in all the modern developments of the museum, the marine laboratory, and the lectureships of botany and geology, the latter specially owing much to his fostering care. Moreover, though he did not, like his talented predecessor, Dr. John Cunningham, profess to study divinity scientifically, yet he took a broad and modern view of his subject, and by his erudition, fine voice, and great lucidity of expression, was ever a popular lecturer and preacher. His first appointment was to the parish of Mains and Strathmartine, near Dundee; his second to the chair of systematic theology in Aberdeen University; and his third to the principalship of St. Mary's College, St. Andrews. He was moderator of the General Assembly of the Church of Scotland in 1911, the year in which the five hundredth anniversary of his own University was celebrated, but after installation in the moderatorship he caught a chill, so that he was only able to appear on the closing day. He exerted himself, however, to fulfil all the other onerous duties during his year of office. In his early days he was an active gymnast and student-president of the University Club, in the welfare of which, as in that of the old University Battery and modern O.T.C., he took a deep interest to the last. As a colleague he gained the esteem of all from his straightforward, genial, and considerate character. His broad sympathies with science and his unselfish and modest bearing won for him the respect alike of colleague and student, as well as gave him a wide circle of scientific friends who mourn his loss.

IN the article upon "The Evolution of the Goniometer," which appeared in NATURE of July 22, it was no part of the historical sketch to give a systematic list of the instrument-makers who had constructed the several types, but since, as Mr. Conrad Beck has pointed out to us, it might appear as if British instrument-makers had not borne their share, we think it right to remove any such misapprehension. Messrs. Troughton and Simms have constructed many fine instruments for, among others, Sir Henry Miers, Dr. A. E. H. Tutton, and the British Museum, and Dr. Hutchinson's universal goniometer, which was described and illustrated in the article, is made by Messrs. James Swift and Son, who kindly lent the block to illustrate the article. In the goniometer, as in all classes of instruments, British manufacurers stand second to none in excellence of workmanship; it is no fault of theirs that owing to the comparative neglect of the study of crystallography in this country they have found so little demand for crystal-measuring apparatus.

IN continuation of the register published in NATURE of July 15 and 22 we are informed that the following

members of scientific staffs are on active service with H.M. Forces:-Plymouth: Marine Biological Association's Laboratory:-L. R. Crawshay, naturalist, Lance-Corpl. 1st King Edward's Horse; E. W. Nelson, naturalist, Lieut.-Commander, Royal Naval Division; J. H. Orton, naturalist, 2nd Lieut. Royal Garrison Artillery; E. Ford, assistant naturalist, 2nd Lieut. 4/2 London Royal Fusiliers. Kingston, Derby: Midland Agricultural and Dairy College :-J. H. Beale, lecturer in horticulture, Lance-Corpl, 2/7th Batt. Sherwood Foresters; F. Knowles, soil analyst, private, 2/7th Batt. Sherwood Foresters; H. M. McCreath, assistant lecturer in agriculture, 2nd Lieut. 8th Royal Scots Fusiliers; J. G. W. Stafford, assistant lecturer in dairying, 2nd Lieut. 11th West Riding Regiment; J. C. Wallace, lecturer in horticulture, Corp. motor despatch rider, Cavalry Corps, Expeditionary Force.

THE Cambridge University Reporter of July 13 publishes the report of the Antiquarian Committee for 1914. In spite of some delay caused by trade disputes, good progress has been made in the erection of the second section of block ii. of the new museum.


divisions of the building will be named after generous benefactors: Messrs. C. E. Keyser, C. C. Babington, and A. A. Bevan. Other donors have provided funds for the fittings of the new building, but the lack of showcases still retards the work of arrangement, and it is difficult to prevent damage to specimens stored away in boxes. A long list of accessions to the collection is given, and the master and fellows of Trinity College are thanked for permitting the transfer on deposit of all the ethnological and antiquarian specimens which had accumulated in the college library. There is still ample opportunity for other benefactors to contribute to this laudable undertaking.

PREHISTORIC cultural centres in the West Indies forms the subject of a brief essay in the Journal of the Washington Academy of Sciences for June. Remarking that the American Indian did not reach America until he had arrived at the Neolithic stage of culture, and did not make acquaintance with the use of metals until introduced after the discovery of America by Columbus, he goes on to point out that as a conseqence of this prolonged use of stone they attained to a higher standard of excellence in the use of this material, both in the fashioning of tools and architecture, than was ever attained by the Neolithic peoples of the Old World. In discussing the remains left by the aboriginal inhabitants of the West Indies he insists that three cultural epochs must be recognised—the cave-dwellers, the agriculturists, and the Caribs. The most primitive of these is found represented by objects

found in the floors of caves or in the numerous shellheaps scattered from Cuba to Trinidad. But the Caribs seem to have been preceded everywhere by the Arawaks, as is shown by the fact that pottery of high excellence has been found on all the islands inhabited by Caribs who, being a nomadic people, had not acquired this art.

THE Journal of the Royal Microscopical Society for June (part 3) contains the presidential address by Prof.

G. Sims Woodhead on "Some of the Micro-biological Problems of the Present War." Prof. Woodhead discusses the question of antiseptic versus aseptic surgery, and is convinced that for the treatment of wounds received on the battlefield antiseptics should be used. The sterilisation of water by means of chlorine and causation of cerebro-spinal fever are other subjects dealt with in this interesting address.

THE lately issued report, No. 3, of the Danish Oceanographical Expeditions, 1908-10, is mainly occupied by K. Stephensen's account of the Isopoda, Tanaidacea, Cumacea, and Amphipoda, many of the species being illustrated by clear outline drawings. P. Jespersen's paper on deep-sea fishes of the family Sternoptychidæ is noteworthy for its detailed distri butional maps. Madame P. Lemoine describes the Calcareous Algæ, illustrating her work with structural figures and a well-printed photographic plate.

AT a meeting of the council of the Ray Society, held on July 22, Prof. E. B. Poulton, vice-president, in the chair, it was resolved to issue for 1916 the second volume of Mr. W. C. Worsdell's "Plant-Teratology," comprising the flower, with twenty-seven plates, several being coloured, and about ninety text-figures, completing the work; and also the second part of vol. iii. of Prof. McIntosh's British Marine Annelids," consisting of twenty-eight plates with descriptions, six uncoloured plates being substituted temporarily for coloured plates, which cannot at present

[ocr errors]

be obtained on account of the war.

A LARGE number of the Annals of the South African Museum (vol. xiii., part 4), published in April, is filled with a paper by Mr. M. Connolly, on South African Mollusca, which he modestly entitles "Notes." The most important of these is a mongraph of the Dorcasiinæ a distinctively tropical and South African subfamily of snails, which are fully described, with anatomical details, and a suggestive distributional discussion in which the author supports the theory of an ancient tropical continental tract stretching from South America by Africa and the Indian Ocean to Australia.

THE last number (vol. xii., No. 76) of the Quekett Microscopical Club's Journal contains an account by Mr. R. T. Lewis of the early history of the club, which, founded on July 7th, 1865, has just celebrated its fiftieth birthday. Its first president was Dr. E. Lankester, and among his successors may be mentioned T. H. Huxley, W. B. Carpenter, A. D. Michael, and B. T. Lowne. Prof. A. Dendy now occupies the chair of the club, and his suggestive address on the biological conception of individuality is printed in the same number. The complexity and difficulty of the subject is well illustrated by his references to the wellknown "border cases of the Siphonophora, Cestoda, Annelida, and the communities of social insects, as well as to abnormal instances of "double personality" in human beings.

[ocr errors]

We have received the first number of vol. ix. of the Quarterly Journal of Experimental Physiology. It scarcely seems that it is as much as eight years ago

that Sir Edward Schäfer founded this new physiological journal, and we wished it good-speed. The publication retains the high standard insisted upon by its editor, and the present number, among the interesting papers which it contains, is specially noteworthy as showing the activity of physiological laboratories in British dominions beyond the seas. One of these comes from Winnipeg, and deals with vasomotor reflexes (by Prof. Swale Vincent and Dr. A. T. Cameron); the other is by Prof. Jolly, of the South African College, Cape Town, and treats of the electro-cardiogram; in his attempt to unravel the meaning of the component parts of the curve he makes the interesting suggestion, and supports it by experimental arguments, that the two phases of metabolism (anabolism and katabolism) which have opposite electrical expressions are responsible for the alternating direction of the variations seen in the electro-cardiogram. Both Profs. Swale Vincent and Jolly are former assistants in Sir Edward's department at Edinburgh.

[ocr errors]

THOSE interested in the study of spiders, and of Indian spiders in particular, will welcome the first of what is intended to be a long series of "Notes on Indian Mygalomorph Spiders" in the Records of the Indian Museum, vol. xi., part 3, by the assistant superintendent of the museum, Mr. F. Gravely. The author makes stimulating comments on the Ischnocoleæ of the the subfamily Aviculariinæ, well represented in the Indian Peninsula, since from their many primitive characters they afford an insight into many evolutionary problems which yet await investigation. The Indian genera of this group seem to present a marked sexual dimorphism, all the known males being distinguished by the more or less extensive and conspicuous development of white hair on the feet, especially the anterior ones. His views on nomenclature and certain aspects of systematics seem to be yet in a state of flux.

ALL who are in any way concerned with the problems of economic ornithology, or of pisciculture, should read the report of Mr. P. A. Taverner on the "Doublecrested Cormorant (Phalacrocorax auritus), and its Relation to the Salmon Industries on the Gulf of St. Lawrence," issued by the Canada Department of Mines (Biological Series No. 5, April, 1915). It is one of the most admirable summaries of its kind ever issued, and is the result of an inquiry instituted by the Geological Survey into the complaints of those interested in the salmon fisheries of the destruction caused to the fisheries by the ravages of the cormorants. The full account of a prolonged and impartial investigation is given in this bulletin, and the verdict arrived at shows conclusively that the harm attributed to this bird is absolutely without foundation. The author shows that while a small percentage of parr are undoubtedly eaten by cormorants, the bulk of the food of these birds is furnished by far less agile fish, having for the most part no economic value. The greatest enemies of young salmon, in the rivers, are older salmon, and the greatest toll on their numbers is taken during their sojourn in the sea by enemies which have yet to be determined. A precisely

similar charge was levelled, some years ago, against the cormorants of the Murray River in Australia, where, to increase the salmon supply, a huge colony of cormorants was wiped out. But the unexpected happened. The salmon disappeared with the birds. It was then found that the latter had been feeding on crabs and eels, which in turn fed upon salmon eggs and fry. With the extermination of their enemies they increased in such numbers that scarcely a salmon egg remained, the fry from such as did escape were eaten by the eels. Those responsible for the massacre of the cormorants are now repentant!

In the Philippine Journal of Science (vol. x., Sec. C, No. 2, March, 1915) Mr. E. D. Merrill publishes the second instalment of his "Studies on Philippine Rubiaceæ." The paper consists of critical notes on the genera Mycetia, Chasalia, Psychotria, and Grumilea in particular, with descriptions of forty-two new species in various genera. The genus Pravinia, hitherto known from Borneo and Celebes with two species in each locality, is now found to be represented in Negros, Philippines, by a new species, P. everettii. Some ninety distinct species of the genus Psychotria are already known from the islands.

MR. Y. TOKUGAWA contributes a paper on the physiology of pollen to the Journal of the College of Science, Imperial University of Tokyo, vol. xxxv., December 17, 1914, a copy of which has just reached us. He finds that suitable osmotic pressure and suitable nourishment are essential for the growth of the pollen tube, and that cane-sugar alone is not sufficient for its growth. Among inorganic salts those of the heavy metals are more injurious than those of the lighter to the growth of the pollen. The pollen tube finds its way to the canals of the style and to the micropyle owing to the presence of a chemotropic substance. A fact of interest which is brought out is that the pollen grains of monocotyledons can germinate on the stigmas of dicotyledonous plants, and vice versa, though pollen grains frequently fail to germinate on the stigmas of plants nearly related to those whence. the pollen was obtained.

Science for May 28 contains an interesting paper on disease resistance in plants, being a lecture delivered by Dr. Otto Appel, of Berlin, at various universities in the United States in October, 1914. The author points out that disease in plants is usually combated by killing the parasite before it enters the host, but the main theme of the lecture concerns the control of disease by breeding disease-resisting plants. As illustrations of the latter method of control, the breeding of rust-resistant wheats, the introduction of Coffea robusta as a plant less susceptible to attacks of Hemileia vastatrix, and the grafting of the European vine on resistant American stocks in dealing with Phylloxera are cited among other cases. There is no mention in the paper of the extensive work on wheats undertaken successfully by Prof. Biffen at Cambridge to produce immune varieties of wheat, nor is Dr. Appel's statement correct that rust has disappeared with the destruction of Barbery bushes, since the summer or uredo-spores have been found

« AnteriorContinuar »