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by making the mean brightness of white (Ao) stars near the sixth magnitude equal to the mean of their visual magnitudes in Harvard Circular 170.
The photovisual scale was obtained in precisely the same manner, isochromatic plates being employed. Final photovisual magnitudes were obtained for 339 stars between magnitudes 2.1 and 17.5. About 300 stars are common to both lists, and for these colour indices are consequently available; for the bright stars this is small, or even negative, at the seventeenth photovisual magnitude the smallest value is 0-6 or 0.7. That the faint stars are all relatively red is thus confirmed.
METEOROLOGY OF THE SUN.-A lecture delivered before the Royal Meteorological Society last March by Prof. W. G. Duffield is reported in full in the Quarterly Journal of the Society. Whilst, of course, primarily adapted to the needs of meteorologists, it is too valuable an essay on the present position of solar research to be neglected by anyone interested in such work. The subject was divided into a number of sections; one of these, dealing with the Te pressure in the sun's atmosphere, has special interest in consequence of Prof. Duffield's own work on the effects of pressure on spectra. Electrical conditions in the sun's atmosphere are considered in another section, containing the interesting suggestion that the "facular masses shown on spectroheliograms owe their luminosity to a continuous display of lightning
between their several parts, or to a bombardment by
negative electrons. Prof. Duffield also suggests that solar rotation is the cause of sun-spots and filaments, this theory being that the differential velocities of the various layers of the solar atmosphere set up vortices; these seen end-on are sun-spots, when floating lengthwise appear as filaments. Although neither of these ideas is entirely novel, yet both go a little further than their precursors.
The paper is illustrated by a number of useful diagrams, and contains reproductions of some fine spectroheliograms.
Min. The light curve of TV Cass. indicates an increase of brightness between primary and secondary eclipse, and the light curve of TX Cass. affords evidence of darkening towards the limb.
SHORT PERIOD VARIABLE STARS.-Von G. Hornig (Ast. Nach., No. 4808) publishes the results of numerous observations by Argelander's method of several bright variable stars of short period. The elements calculated from these observations, together with mean light curves, are given for the three Cepheid variables RT Auriga (74 obs.), Aquilæ (190 obs.), 8 Cephei (396 obs.), for the Geminid variable Geminorum (171 obs.), and for the two stars of B Lyræ type, u Herculis (208 obs.) and ẞ Lyræ (327 obs.). Elements determined by Breson from observations of Geminorum, Aquilæ, & Cephei, and B Lyræ, and by Lau in the case of 8 Cephei and B Lyræ, are compared. It is stated that the lack of correspondence in the secondary maxima of light curves determined by different observers is due to their varied "colour-perception," as are also the minor differences of more or less pointed or flattened maxima.
THE MANCHESTER MEETING OF THE
AS already announced, the meeting will be opened
In Section B there will be an exhibition and ex
VARIABLE STARS.-Two papers dealing with inves-planation of diagrams by Dr. Dalton, illustrating his tigations carried on at Princeton Observatory appear in the Proceedings of the American Philosophical Society, No. 216. In one of these Dr. Dugan (p. 54) gives some recent results obtained in the case of the eclipsing variables RT Persei and Draconis, both cases where the light curves have demonstrated ellipticity of figure, exchange of radiation, and possibly darkening at the limb. For RT Persei the shape of the light curve possibly indicates that the advancing side of the brighter component is brighter than the following. Some recent observations of the secondary minima show that the eclipses are now coming forty minutes earlier than the times predicted from the original elements derived from observations taken about seven years ago. Extending the period of observation by data from Harvard results in a reduction of the average period by one second. Using this shorter period the residuals reveal two periodic terms, the shorter of which closes in about 4000 eclipse periods, i.e. about nine years, and with a coefficient of five minutes. This is of the order of magnitude of that to be expected from the revolution of the line of apsides caused by the observed prolateness. Necessary additional observations are being undertaken. Similar results have been obtained for z Draconis. In both stars the light at minimum is distinctly redder than before. In the other paper Mr. R. J. McDiarmid deals with the algol variables, TV, TW, TX Cassiopeiæ, and T Leonis Minoris. Secondary minima have been established in the light curves of TW Cass. and T Leo.
atomic theory, an experimental paper by the Hon. R. J. Strutt on active nitrogen, a discussion on smoke | prevention, experimental papers on combustion, a paper by Prof. W. J. Pope on liquid crystals (with experiments), and a discussion on homogeneous catalysis.
In Section C Dr. G. Hickling will give an account of the geology of Manchester and district; Prof. W. Boyd Dawkins, papers on the classification of the tertiary strata by means of the Eutherian mammals, and the geological evidence of the antiquity of man in Britain. There will be a joint discussion with Section E on the classification of land forms (opened by Dr. J. D. Falconer). Papers will be read by Dr. A. H. Cox and A. K. Wells on the Ordovician sequence in the Cader Idris district (Merioneth); Prof. T. G. Bonney, on the north-west region of Charnwood Forest; Dr. A. Vaughan, on the shift of the western shore-line in England and Wales during the Avonian period; Prof. W. G. Fearnsides, on a contour map of the Barnsley coal seam in Yorkshire. A discussion on radio-active problems in geology (opened by Sir E. Rutherford). Papers will be read by Prof. Č. A. Edwards on twinning in metallic crystals; Prof. W. J. Sollas, on the restoration of certain fossils by serial sections; Dr. J. W. Evans, on the isolation in the directions image of a mineral in a rock-slice; Dr. G. Hickling, on the micro-structure of coal; D. M. S. Watson, on vertebrate life zones in the Permo-Trias; Dr. A. Wilmore, on the Carboniferous limestone zones of north-east Lancashire; H. Day, a brief criticism
of the fauna of the limestone beds at Freak Cliff and Peakshill, Castleton, Derbyshire; Dr. Jowett, a preliminary note on the glacial geology of the western slopes of the southern Pennines. It is intended to arrange, if possible, two or three afternoon geological excursions in the neighbourhood of Manchester. On Saturday there will be a whole-day field excursion to Edale and Castleton.
In Section D there will be the following communications:-A discussion on chromosomes and heredity (to be opened by Prof. E. W. MacBride), and a series of papers on material collected in or en route to Australia in connection with the visit of the association last year. Prof. Herdman will contribute notes on the plankton collected between Liverpool and Fremantle (via the Cape), Dr. J. H. Ashworth will give an account of larvæ of Lingula taken in the Red Sea and Indian Ocean, Prof. Dendy will give notes on his collecting in Australia, and Prof. Poulton will exhibit insects taken in Australia. Launcelot Harrison will give a paper on the relation of the phylogeny of the parasite to that of the host. He will advance the views that in the case of total obligate parasites, closely related parasites will be found to occur on phyletically connected hosts, and therefore the study of such parasites may give valuable indications as to the phylogeny of the host; for instance, the Mullophaga found on the New Zealand Apteryx indicate that this bird is a Ralline bird, and not a Ratite. Lieut.-Col. Lieper will give a demonstration upon his recent work on Bilharzia in Egypt, during the course of which he has been able to elucidate the life-history of this parasite of man. Other papers promised are:-Prof. F. J. Cole and N. B. Eales, materials for a graphic history of comparative anatomy; Prof. Hartog on the movements of chromosomes in cell-division; Prof. Hickson on the distribution of sea-pens; Dr. Dixey and Dr. Cameron on entomological subjects; Prof. Meek on the distribution of fish and (another paper) on the future of scientific literature in relation to the war; Dr. J. S. Thomson on the elasmobranch fore-brain; Dr. W. C. Mackenzie on the vermiform appendix in Monotremes and Marsupials; Dr. C. Powell White on the regeneration of the tail in lizards; F. W. Ash on secondary sex-characters.
The arrangements for Section E are:-Papers by A. R. Hinks on the map on the scale of 1: 1,000,000; O. J. R. Howarth on geographical considerations arising out of the visit to Australia in 1914; Prof. J. W. Gregory on relations of the central lakes of Westralia; Dr. R. N. Rudmose Brown on the growth of cities in Australia; J. McFarlane on the Burrinjuck dam and the Yanco irrigation area; a joint discussion with Section C on the classification of land forms; a joint discussion with Section H on racial distribution in the Balkans (opened by Prof. G. Elliot Smith); papers by P. M. Roxby on north China and Korea; Dr. R. N. Rudmose Brown on Spitsbergen before the war; R. Curtis on the distribution of population in the district round Leek; T. Edwards on a rainfall map of Lancashire and Cheshire; Dr. F. Oswald on a recent visit to the Caucasus; J. Parry on lake movements as observed in Lake Vyrnwy, and one on afforestation, being continuation of the paper read at the Southport meeting in 1903.
Among the papers to be read in Section G are:Prof. Asakawa and Prof. Petavel on an experimental investigation of the thermal efficiency of a gas engine; Prof. W. M. Thornton on the apparent specific heats in gaseous explosions; E. C. Mills on a unit gasproducer for steam boilers; A. A. Griffith on an investigation of the thermal conductivity of thin-air films; Prof. Batho on torsion stresses in framed
structures and thin-walled prisms; A. Robertson r the strength of iron and steel struts; Dr. Eccles ar A. J. Makower on electric oscillations in couple circuits; Prof. G. W. O. Howe on the capacity aerials of the umbrella type; Prof. Miles Walker (the eddy current losses in the end-plates of larg turbo-generators; Prof. Walker will also describi some experiments to determine whether there exist. mutual induction between masses; Prof. W. Morgan on the automobile and war; T. H. Brigg will descrit a new method of attaching horses to vehicles.
In Section H the president's address will be ic' lowed by a discussion (to be opened by Prof. EL: Smith) on the influence of ancient Egyptian civilisa tion on the world's culture; Prof. Flinders Petrie will deal with Egyptian jewelry, describing in per ticular the treasure of Lahun; Dr. Alan Gardiner will discuss the evidence pointing to a common paren for the Phenician, Greek, and Sabæan alphabers afforded by the inscriptions on strelæ, undecipherable as any form of Egyptian writing, discovered by Prof. Petrie at Sinai in 1905; Prof. Giuffrida-Ruggeri, c Naples, has forwarded a paper on the racial origins of the early Neolithic and copper-using peoples of Egypt, which will be presented and discussed by Prof. Elliot Smith, and Miss Margaret Murray, in a communication on royal marriage and matrilineal descent, and Mr. Hocart, in a paper on the quest for immortality, will be concerned largely with the Egyptian evidence. Racial distribution in the Balkans will form the subject of a discussion in joint session with Section E. Papers will be read by R. M. Dawkins on the Greek element in Asia Minor; and Dr. Rivers on analysis of ceremonial and descent in Ambrim. In physical anthropology Prof. Keith will present and discuss, at the request of the author, une Application anthropologie à l'Art militaire, by Prof. E. Manouvrier, of Paris, which deals with the desirability of classifying troops acording to certain anthropological characters; and Prof. Elliot Smith will exhibit the most ancient human remains from India. There will be a visit to the Roman fort at Ribchester, the exploration of which has been carried on under the auspices of Manchester University. The main features of the fort will be described by Prof. Haverfield, Prof. W. B. Anderson, who has been in charge of the excavations, and others.
In Section I it was hoped to have had a discussion on the physiological conditions necessary for the maximum efficiency of the factory worker, but the absence, owing to circumstances created by the war, of so many who could have spoken authoritatively on the subject has necessitated its deletion from the programme. Prof. B. Moore is giving a popular lecture during the meeting, in which he will have a good deal to say on the physiology of factory labour. Prof. Bayliss is to speak on the mode of action of urease; Dr. Edridge-Green on some fundamental facts of vision and colour vision; and Prof. B. Moore on the action of light on certain inorganic and organic substances. Some local contributions are kinematograph films by Dr. Graham Brown; the presence of copper in animal and vegetable tissues by Dr. C. Powell White; some laws of fat absorption, and the micro-chemical differentiation of tissue fats and lipoids, by Drs. Lamb and Holker. Dr. C. E. Lea is to give a demonstration of the detection of certain cardiac disorders by the electrocardiograph. Other contributors are Dr. Sarah M. Baker, on the liquid pressure theory of muscular contraction; Prof. W. H. Thompson on arginine and creatine formation, and on the effects of tetanisation on the creatinine and creatine of the muscles of the cat; Dr. John Tait on thrombokinase; Drs. Tait and Pringle on the elas
ticity of the strophanthinised heart; and Prof. P. T. Herring on the effect of thyroidectomy on the adrenincontent of the suprarenals.
In Section K a lecture is to be given by W. Lawrence Balls on cotton, and the following papers will be read :-Prof. F. O. Bower on the evolution of some ferns, in particular the Dipterids and the allies of the common bracken; Dr. D. H. Scott on the fossil plants of the genus Heterangium; Dr. Marie C. Stopes on the fossils of the Aptian (Greensand) period, including some of the oldest flowering plants of this country showing internal structure; Prof. Osborn on the morphology of Selaginella uliginosa, and his wife
some Australian fossils belonging to the genus Zygopteris; Dr. Ellis on fossil bacteria and fossil fungi; Dr. Sarah M. Baker on a new hypothesis regarding the ascent of sap in plants; Dr. Marion Delf on the effect of temperature on the permeability of protoplasm to water; Miss Prankerd on Statoliths; Prof. W. B. Bottomley on the formation of auximones from nitrogenous organic substances; Prof. Julius MacLeod on the expression by measurements of specific characters with special reference to the mosses; Dr. J. C. Willis on the evolution of the flora of Ceylon.
In Section L the following discussions may be expected :-On methods and content of history as a subject of school study; on military training in schools; on education of women in relation to their careers; on education and industry.
In Section M papers will be read by Prof. J. Hendrick on composition and uses of seaweed; by Prof. W. Somerville on accumulation of fertility in grass land; by D. Macpherson on types of hill grazings, their economic value and importance; and discussions will take place on probable effects of the war on the future of British agriculture, and the economics of milk production.
THE STUDY OF HEREDITY.
HE popularity of problems of genetics as subjects for research and discussion is well illustrated by the May number of the American Naturalist (vol. xlix., No. 581), every paper in which bears on one or other of such problems. Of especial interest is Prof. Jacques Loeb's article on the nature of the conditions which determine or prevent the entrance of the spermatozoon into the egg. It is well-known that in normal fertilisation, the entrance of the spermatozoon is followed by the formation of a membrane around the egg, so that the entrance of other spermatozoa is prevented. But, as Prof. Loeb has already recorded in his work on "Artificial Parthenogenesis and Fertilisation," seaurchin eggs the development of which has been started by treatment with hypertonic sea-water can be afterwards fertilised, a spermatozoon being capable of entering a blastomere at least up to the stage of the eighth cleavage-and inducing a distinct and clear membrane formation" around it. This shows that the entrance of a male cell is not necessarily prevented by "the changes underlying development." But eggs by treatment with butyric acid can be induced to form a membrane. If this membrane remain unbroken subsequent fertilisation becomes impossible, though parthenogenetic segmentation may begin; if, however, the membrane be ruptured by shaking, a spermatozoon can enter and the egg undergoes normal development. Hence it may be inferred that the physical condition of the surface of the egg-howsoever modified-is the immediate determinant of the admission or exclusion of a spermatozoon. This view is supported by Loeb's experiments in cross-fertilisation, which show that the sea-urchin (Strongylocentrotus) egg admits the sperm
alkaline solution. On the other hand, eggs cannot be fertilised by sperms of their own species in sea-water containing an excess of neutral chlorides. From all these facts Loeb is inclined to draw the conclusion that the tension of the surface of the egg may explain the engulfment or exclusion of the spermatozoon. But it is obvious that in the case of normal fertilisation this surface-condition is "induced from within the egg by changes caused by the entrance of the spermatozoon"-a deduction made by biologists long before the study of "experimental embryology" had become fashionable.
In the same number of the American Naturalist Dr. Raymond Pearl continues his studies in heredity with reference to questions of practical breeding with a paper on Mendelian inheritance of fecundity in the domestic fowl." Large egg-yield, especially during the winter months, is shown by experiment to depend upon the presence of two Mendelian factors in the germ-cells, so linked with sex-determining characters that the female is heterozygous. Thus is confirmed the belief of some poultry-fanciers that the father is of greater importance than the mother for the establishment of a "good laying strain." In the Biological Bulletin (vol. xxviii., No. 3) Dr. M. R. Curtis describes a Rhode Island red hen with the terminal part of her oviduct aborted. Consequently the eggs--which were produced in the normal way-passed out into the body cavity and their food materials were absorbed by the bird's tissues without disturbance of the metabolism.
A recent number of our British Journal of Genetics (vol. iv., No. 4) contains a noteworthy paper, by Dr. H. Drinkwater, on the inheritance of brachydactyly in human families. The observations on this condition made by Dr. W. C. Farabee in North America, and by Dr. Drinkwater in this country are summarised in Mr. Bateson's book, "Mendel's Principles of Heredity," and brachydactyly has become a classical example of a simple Mendelian dominant-character. Dr. Drinkwater now describes a second family in England, and proves it to be a branch of the American stock studied by Dr. Farabee. The most important feature of the present study is found in the very beautiful series of radiographs of the brachydactylous hands and feet. The second phalanx is not really absent, but remains in a rudimentary condition, and becomes usually united to the base of the terminal phalanx.
Colour phenomena in animal and plant inheritance naturally continue to attract the attention of experimenters. A short paper on the "English" rabbit, by Prof. W. E. Castle and P. B. Hadley (Proc. Nat. Acad. Sci., vol. i.) is worthy of note. The "standard" coat in these rabbits is white with black muzzle, ears, and spots on back and flanks. Breeding experiments have shown that this "standard" coloration is really a mark of hybridity, for when mated together such rabbits yield a progeny half of which are either without the back and flank black markings or with these greatly exaggerated. The present paper describes how a "standard English" buck was mated with "Belgian hare" does, and how one of his dark-coated sons from this cross was afterwards mated to the same does; the result was that this latter begot distinctly darker offspring than his father, the "modal grades being respectively 2.0 and 3.25. "Yet the father," write the authors, "contained only a single dose (one gamete) of English pattern, and the son derived his English pattern exclusively from this same source. Hence the English unit-character had changed quantitatively in transmission from father to son. seems to us conclusive evidence against the idea of unit-character constancy or gametic purity."
Dr. L. J. Cole's paper on the inheritance of colour in pigeons (Rhode Island Agric. Exp. Station, Bulletin
of an echinoderm of another class only in a hyper-158) was summarised in NATURE last year (vol. xciv.,
p. 213). The same subject has now been further investigated by Mr. D. Lloyd-Jones (Journ. Experimental Zoology, vol. xviii., No. 3) in a microscopical and chemical study of the feather-pigments. colour is due to red-brown pigment-granules which are present in the intermediate cells of the epidermis as well as in special pigment-cells. This pigment, if very finely divided, produces yellow. Black pigment under various conditions produces black, dun, blue, or silver.
Pigeons serve also as the subject of an inquiry into "Sex Ratios" by Drs. L. J. Cole and W. F. Kirkpatrick (Rhode Island Agric. Exp. Station, Bulletin 162). The normal ratio calculated from a large number of broods is 105 males to 100 females, and the death-rate is especially high for the first three days after hatching and at the age of about a fortnight. It is well known that the pigeon's normal brood consists of two eggs. In the recorded cases there were 284 bisexual broods to 302 unisexual; of the latter 149 consisted of two males and 153 of two femalesa result indicating almost perfect equality. The deathrate of males and females in the bisexual broods is essentially equal. "A comparison of the numbers of each sex hatched from first and from second eggs respectively shows no tendency for the former to produce exclusively males and the latter females, but more The males than females are hatched from both." authors conclude that "sex in pigeons is determined according to the laws of chance"-in Mendelian terminology the individuals of one sex are heterozygous, and those of the other homozygous as regards the sexdetermining factors. G. H. C.
BIOMETRICS AND MAN.
IN part iv. of vol. x. of Biometrika, Mr. H. Waite publishes an interesting study, based on two thousand complete sets of finger-prints of adult males, part of a series in the biometric laboratory, University College, London. It appears that the various types of finger-print are not scattered at random over the fingers; certain types are more or less peculiar to certain fingers, and the appearance of one type is associated with that of another. In this respect certain fingers are more closely related to each other than to any third finger, and the distribution of this relationship is in general similar to that of the correlations of the bones of the same fingers. In the same number, Dr. Alice Lee discusses the influence of segregation on tuberculosis, a question to which much attention has been devoted of recent years. No method of measuring the extent of segregation is, however, found satisfactory, and the various methods used, for example, by Dr. Newsholme, lead, when examined by more stringent methods, to contradictory and inconclusive results. Whether there is any really substantial relation between the prevalence of phthisis and institutional segregation may remain an open question, but Dr. Lee is of opinion that no such relation has been demonstrated. Miss Elderton and Prof. Pearson similarly fail to find any evidence that isolation reduces the attack-rate from diphtheria; no appreciable influence on the attack-rate is found in certain data placed at their disposal by the medical officer of health for Coventry, though the death-rate may be lowered.
series of years, is high and positive. But the corre's tion of first differences is negative, and this negata. correlation increases in intensity as higher and hig differences are taken, until fairly steady values are reached for the sixth differences, ranging round Thus for males the correlation of sixth differences the first and second years of life is 0.688, in the fourth and fifth years of life -0.695. For females t corresponding figures are -0.719 and -0736. The correlations in each case are taken between death-rateof those born in the same year. At an interval of tw years the partial correlations are negative but much lower; at three and four years' interval the signs are irregular and the results inconclusive. To assert the existence of selection and measure its intensity, the authors remind their readers, must be distinguished from advocacy of a high infantile mortality as a factor of racial efficiency.
We can only briefly direct attention to two articles by Mr. R. A. Fisher on the frequency distribution of the correlation coefficient in samples from an indefinitely large population, and on the distribution of standard derivations of small samples.
REPORTS ON MINING INDUSTRIES.
TWO reports issued by the Canadian Department of Mines ("Peat, Lignite, and Coal," by B. F. Haanel; "Report on the Non-Metallic Minerals Used in the Canadian Manufacturing Industries," by Howells Frechette; Ottawa, 1914) are further examples of the sedulous care with which the Canadian Government is endeavouring to foster the industry of mining in the Dominion. The report upon peat, lignite, and coal deals exclusively with the application of these fuels to the generation of power-gas and to the recovery of by-products, the latter being chiefly ammoniacal salts. An elaborate study has been made of the various methods of dealing with peat in Europe, although, for some reason not easy to understand, Russian practice appears not to have been included, in spite of the fact that conditions in Russia resemble more closely those in Canada than do any of the other countries investigated. The first part of the report is taken up with a discussion of the various methods of producing peat fuel; it is interesting to note that the author has devoted a good deal of attention to the well-known Ekenberg process of wet carbonisation, and that his conclusions are decidedly unfavourable to the process. He points out that the most recent report on the subject by Lassen shows "that in continuous operation on a large scale, a moisture content below 70 per cent. in the pressed cake cannot be counted on," and dismisses the subject with the following statement:
"Although large funds have been placed at the disposal of various investigators in order to enable them to demonstrate the economic value of the process, and although a private company has conducted elaborate experiments on a large scale, involving the expenditure of a large amount of money, not one ton of peat fuel has been manufactured on a commercial scale by means of this process.'
The author's opinion of the Brune and Horst process for pressing out the water is equally unfavourable, nor is he greatly impressed by the possibilities of any of the methods of artificial drying, and sums up in favour of air-dried peat. He shows that under normal Canadian conditions peat can be utilised to advantage for the production of gas provided that it contains not more than 40 per cent. of moisture and that it can be obtained at a cost not exceeding 1.50 dollars (6s. 3d.) per ton of peat containing 30 per cent. of moisture. He holds
that the recovery of ammonia is not likely to be profitable unless the nitrogen content exceeds 1 per cent. calculated upon absolutely dry peat. Finally, he shows that under favourable conditions power can be generated from certain of these Canadian peat bogs at a cost equal to or below that at which it can be obtained by the utilisation of water-power. A little attention is also devoted to the question of the utilisation of the lignites of certain of the Western Provinces, where true bituminous coal is not obtainable locally, and it is shown that in certain circumstances it too can be employed profitably in the generation of gas.
The second report is intended to aid, not only the mining industry, but also the very large number of manufacturing industries that depend to a greater or lesser extent upon an adequate supply of raw materials in the shape of mineral products. The report deals with a very large number of miscellaneous minerals, of which asbestos, barytes, clay, lime, and sand are perhaps the most important, and it should be noted that such minerals as are used in Canadian manufactures but are not produced in Canada are referred to, as well as the minerals of domestic production. It is noteworthy that quite a considerable quantity of minerals is imported, although they could be produced in the Dominion, and one of the main objects of this report is to bring actual or possible producers
and consumers into closer touch with one another. The object is an excellent one, and such reports as this should prove of the greatest value to both parties and should help towards that very desirable object, the industrial independence of this great Dominion.
The report of the Chief Inspector of Mines of the State of Mysore for the year 1913 has just been issued. Apart from the statistical portion, which shows that the value of the bullion produced during the year in question was 2,150,1931., a decrease of 0.37 per cent. from the previous year, the chief general interest in this report is to be found in a careful investigation of a shaft accident at the Mysore Gold Mine. It appears that the steel pin, which secured a driving clutch, that connected the engine shaft and the winding reel suddenly broke, allowing the cage, in which forty-two miners were travelling, to fall to the bottom of the shaft. An investigation was held into the cause of the fracture of this pin and into the reason why the powerful brake attached to the winding engine did not hold the reel, and the report of the committee of inquiry is now given. It cannot be said that the cause of the fracture is satisfactorily explained, but the insufficiency of the braking arrangements is very clearly demonstrated. Having regard to the fact that this brake is of the construction that is in general use on winding engines in all parts of the world, this report deserves the careful attention of all who have to do with winding from deep shafts by means of the powerful winding engines that are in general use in modern mines; in particular it may be noted that the brake appears to have complied fully with the provisions of our Coal Mines Act, and yet was found inadequate to prevent the very serious accident in question.
Another interesting section in this report deals with accidents due to "air blasts," which caused no fewer than thirty-one deaths during the year in question. These air-blasts consist in the sudden flying-off of huge masses of rock from the walls of stoped-out portions of the deposit, the action being extremely violent and suggesting that the rock is under some condition of great strain that suddenly relieves itself. The phenomenon is as yet but little understood, and all measures taken for combating this danger are still of a more or less tentative character.
TRYPANOSOMES CAUSING DISEASE IN MAN AND DOMESTIC ANIMALS IN CENTRAL AFRICA.1
HESE lectures are confined to a consideration of the trypanosomes causing disease in man and domestic animals in Central and Southern Africa. The conditions, however, which obtain on the east and west coasts of Africa between 20° N. and 30° S. latitude are much the same as those which are found in the central parts, and it is probable that the same trypanosome species are found throughout. So that in describing the species found in our own colonies it may be assumed that all the important pathological species found in Central Africa are being dealt with, although in other places they may be known by other
The central region-the tropical or equatorial-corresponds with the distribution of the tsetse-flies, and the trypanosomes causing disease in this region are carried from sick to healthy animals by various species of this genus of flies. In the north of Africa, outside the range of the tsetse-flies, two trypanosome diseases are found, one of the horse (dourine), and another of camels (surra), the former conveyed from sick to healthy horses by contagion, the latter almost certainly by large biting flies, the so-called horse-flies, or
Group A. Trypanosoma Brucei Group.
1. Trypanosoma brucei.
2. Trypanosoma gambiense.
4. Trypanosoma equiperdum.
Group B. Trypanosoma Pecorum Group.
Group C. Trypanosoma Vivax Group.
These names probably represent most of the principal pathogenic trypanosomes discovered up to the present time in Africa. The northern species, Trypanosoma evansi and T. equiperdum, are placed in the first group, as they seem by morphology and their action on animals to belong there. Each group is distinguishable or separable by well-defined char
Group A. The Trypanosoma brucei Group.-The species forming this group (Fig. 1) are all more or less polymorphic, varying in size and shape from short and stumpy forms without free flagella to long and slender forms with free flagella. The cytoplasm contains numerous dark-staining granules. The micronucleus or kinetonucleus is small, and is situated as a rule some distance from the posterior extremity. The undulating membrane is well developed and thrown into bold folds.
1 Abridged from the Croonian Lectures delivered before the Royal College of Physicians of London on June 17, 22, 24, and 29, by Sir David Bruce, C. B., F.R.S.