close to the stem, the projecting stump decays, and the decay affects the trunk. Where branches are not pruned at all, or not at the right time, natural pruning caused by thick planting occurs, but the decay of the branches also affects the trunk. Too early thinning prevents the growth of clean boles with suppressed branches. All these points require careful attention in forestry, or considerable depreciation in the value of the timber ensues. The Royal Agricultural Society, the Royal Agricultural College, the Surveyors' Institution, and Mr. A. T. Gillanders (forester to the Duke of Northumberland) sent collections of mounted specimens of insects injurious to forest trees. Those of Mr. Gillanders were very complete, and were classified as beetles, saw-flies, moths, scale insects, aphidæ, and diptera.

Nature-study in Rural Schools.

44

(Amraphel, King of Shinar), a passage in the Song of Songs about the cessation of winter and stoppage rains, a plant crowning the mummy of an Egyptian princess, Quintus Curtius's account of Bactria in the time of Alexander, down to the investigations of Heim, Hess. Bruckner, and Russian explorers. The writer adduces experiences of the Aral region in support of his conclusions. In 1896, 1897, and 1899 Mr. N. A. Busch was conmissioned by the Imperial Russian Geographical Society : investigate the glaciers of the western Caucasus, Kuban district, and Sukhum circle. The results are recorded in his report, Glaciers of the Western Caucasus," 1005 (134 pages), which is furnished with a helpful index and some fine views.

A work entitled "Materials for the Geography of the Urals," by Mr. P. Krotov, describes orohydrographical

groups of exhibits from public elementary schools,

secondary schools, and school gardens. The counties from which exhibits were sent included Cambridge, Cumberland, Durham, Derby, Essex, Leicester, Lincoln, Nottingham, Stafford, Suffolk, Sussex, and Worcester, and the work sent was highly creditable to both teachers and scholars. It was stated that the specimens were collected and mounted by pupils of average intelligence, but the excellence of many of the water-colour drawings of common flowers was remarkable. The collections made by the scholars included mounted specimens of local flowering plants, some of them classified into hedge-row, wood, and water plants, collections of tree leaves, autumn fruits, fossils, common insects, snails, wireworms, &c. In the secondary schools the work was, of course, more advanced, and included classification into seeds, seedlings, branches, flowers, fruits, and wood in the case of common trees. The Staffordshire County Council exhibited collections of tools, seeds, and apparatus as supplied to school gardens, and a map showing that gardening classes are held in seventy-nine day schools, in thirty evening schools, and two grammar schools in that county. The introduction of nature-study into our rural schools appears to hold out great promise as a means of training and developing the intelligence of country children. It should go far to counteract that "dulness of the country" which is stated to be one of the potent causes of migration to the towns. Education of the youthful mind to the intelligent appreciation of natural phenomena may be regarded as a most important means of ensuring the future progress of agricultural science. E. H. G.

RUSSIAN GEOGRAPHICAL WORKS. SEVERAL papers and memoirs of scientific interest and importance are included in publications received from Russia during the past few months. The publications are printed in the Russian language, and among them are four volumes of the Proceedings of the Imperial Russian Geographical Society.

In vol. xli., part iv., of the Proceedings of this society, Mr. V. V. Markovitch contributes lengthy articles, one entitled "In Search of Eternal Ice," and the other on the ice-fields of the Caucasus, illustrated with beautiful photographs and sketches. Botanists will be interested in his notes on the flora of the mountains. Elaborate reports on the subject of ground ice, by a commission appointed to study the question, appear in the Proceedings, vol. xli., part ii. A map of European Russia is given, indicating results of investigations by many observers. In vol. xl., part iv., an important examination by Mr. A. I. Voieikoff of the question whether the Pacific Ocean will become the chief commercial route of the terrestrial globe appears, with statistics and maps.

In vol. xli., part iii., Mr. L. Berg differs from Prince P. Kropotkin's opinions on progressive desiccation of EurAsia, maintaining that the climatic conditions of Central Asia have been practically unchanged from the earliest recorded times, and that geological desiccation has long ceased. Mr. Berg refers to a canal called after Hammurabi

range. The preface opens with a reference to Dr. Carl Hiekisch's work" Das System des Urals" (Dorpat 18821 is meagre and superficial owing to lack of expenditure of to show that knowledge of the geography of these regions

money and exertion. It is claimed that the northern and

The six chapters contain :-historical sketch of previous explorations; cartographical materials and geological sketch; orographical description; hypsometry of the western slope of the Urals; hydrographical description: concluding notes; "absolute heights in the southern part of the central Urals; forty-two pages of lists of heights. Orographical and geological charts are given at the end on a scale of five versts to the inch.

The report of the Imperial Russian Geographical Society for the year 1904 contains a vast amount of useful matter. especially in the records of scientific exploration. Following the official lists there are short biographies of deceased members, including General P. S. Vannovsky and Admiral S. O. Makaroff, medallist, constructor of the ice-breaker Yermak.

The society regrets that owing to unavoidable hindrances many undertakings had to be abandoned. About six pages are devoted to the exploration conducted by Mr. A. V. Zhuravsky of the Bolshezemelsky tundra, starting from the Petshora, and including the river Adzva, the Vashutkin Jakes, and the Adak ridge. Samoyed natives assisted as guides. As a result, some important local points were made clear, collections of flora and water fauna, molluscs, and spiders were made, besides a herbarium, map of the lakes and rivers, photographs, meteorological report, and statistics of the native population-which is in danger of dving out-were collected. In the Proceedings of the society, vol. xli., part iii., 1905, Mr. A. Rudneff contributes a preliminary report of this expedition, with illustrations. This region has only been traversed twice previously, by Mr. William Gourdon, of Hull (1614-1615), who left a diary, and by Herr A. Schrenk (1837), author of an account of travel in north-eastern European Russia. Mr. A. V. Zhuravsky's letter to the secretary, in which he relates his activities and mentions the establishment of a zoological station at Ustzilma, appears in vol. xli., part iv.

Mr. A. A. Makarenko made an ethnographical expedition to the Yenesei government, and collected songs and information on local medicine. Other important explorations in Turkestan and the southern steppes are reported. Condensed reports of the ethnographical and other sections, financial statements, publications issued and received, and miscellaneous notes complete the volume.

The Russians have accumulated a vast amount of material with regard to the customs and literature of the Turks and Tartars, the results of researches in fields practically inaccessible to Western scholars.

"The Story of Yedigei and Toktamysh," edited by Prof. P M. Melioransky, consists of a preface, glossary, and nearly forty pages of Kirghiz text (in Arabic characters) of an old tradition concerning some of the leading members of the famous Golden Horde, temp. later fourteenth and earlier fifteenth century. Khan Toktamysh, after the defeat of the Khan Mamai at Kulikovo-polie by the Grand Duke Dmitri Donskoi, in the following year attacked and burned Moscow. Yedigei was a specially distinguished emir under Toktamysh, and, according to the story, was the son of 4 holy man, Hodzha Amet, and a mysterious, aqueous being with a goat's feet and a transparent body, upon whom her husband does not gaze when she removes a garment for fear she should wish to leave him. Timour or Tamerlane, styled in the story Sa' Temiru, revered the memory of the Hodzha and protected his son. From being a follower of Toktamysh, Yedigei induces Timour to make war on him, and is credited with a similar judgment to that of Solomon in a parallel case of maternal controversy.

The tradition exists among the Nogai, Kirghiz, and Siberian Tartars in varied form. We are not in a position to criticise the text of the poem, and the learned editor

hints at a vast wealth of Tartar tradition still to be collected and arranged for publication.

THE MATTEUCCI MEDAL. THE Italian Society of Sciences known as the Society of the Forty has awarded the Matteucci medal for 19c5 to Sir James Dewar in recognition of his scientific work. In presenting the report upon the award, the committee of the society, consisting of Profs. P. Blaserna, A. Righi, and A. Roiti, referred to Sir James Dewar's researches in the following terms :

James Dewar, born in 1842 at Kincardine-on-Forth in Scotland, completed his studies and took the first steps in his professorial career in the University of Edinburgh ; in 1873 he was appointed professor of natural philosophy at Cambridge, from which post he was promoted Fullerian professor in the Royal Institution in London, where he is likewise director of the laboratory founded in memory of Davy and Faraday.

We shall not pause to enumerate all the contributions which he rendered to the knowledge of aromatic compounds, nor the other important investigations in chemistry 1 Sa, it is explained, is a form of the word Tsar (Cæsar).

by which he initiated his scientific career. But we cannot omit to point out the work which he carried out from 1878 to 1890, for the most part in conjunction with Prof. G. D. Liveing, of Cambridge, which work undoubtedly forms part of the finest that has yet been produced in the field of spectrometry. This work is set out in about fifty short notices free from all preconceived ideas and admirable in their experimental genius, enriched with data meriting the highest attention and universally accepted, and fertile in their theoretic bearing and scope. Dewar and Liveing were the first to investigate the phenomena of inversion in many elements; afterwards they studied the influence of temperature on the spectra of the same elements, and the way in which these spectra were modified by the presence of other elements. Extremely interesting are their researches regarding the various spectra of carbon and its compounds, and in relation to the phenomena of synthesis manifested in the electric arc. They, moreover, furnished the first exact determinations of the ultra-violet spectral region, assigning with the utmost care the wave-lengths for a fair number of elements.

Various other problems made evident Dewar's extraordinary experimental ability, and his world-wide fame was secured by the problem, more than any other, of obtaining extremely low temperatures, to which he has indefatigably and courageously devoted himself for more than twenty years, with the satisfaction of seeing his labours crowned by the liquefaction and solidification of hydrogen, which allowed him to study the chemical and physical properties of gases formerly held to be irreducible, when they have changed their state of aggregation.

Having ingeniously contrived means for rendering inconsiderable the losses by evaporation of these new and highly volatile liquids, and thus for preserving them for a length of time in large quantities, he turned this to able account in order to investigate the very varied phenomena which took place at their boiling temperatures, low in themselves, and still further lowered by expansion.

Most extensive is the field covered by Dewar in his studies of this kind: variations of density and cohesion, chemical and photographic actions, phosphorescence and radio-activity, optical properties, thermoelectricity, electric conductivity and inductivity, and magnetic susceptibility. It would take too long to enumerate here the important and partly unexpected results obtained by him, and indeed it is superfluous, as they are present in the minds of all. Let us rather restrict ourselves to accompanying the Matteucci medal, which we award him, by the wish that from the 13°, which he has already reached, he may descend still further downwards towards absolute zero, and succeed in liquefying even helium.

PRACTICAL METEOROLOGY.

THE Meteorological Committee has issued its first report, for the year ended March 31, 1906. In compliance with the desire expressed by H.M. Treasury, the work of the office proceeds generally on the lines hitherto followed, and the committee record" their appreciation of the services rendered in the administration of the office by Sir R. Strachey, the chairman of the council for twentytwo years, and by other members. An important addition has been made by participation in the investigation of the upper air by means of kites. It is also proposed, if practicable, to make use of unmanned balloons, and to render the service more effective by cooperating with the representatives of other bodies concerned in the work. Among some of the useful researches initiated or completed during the past year may be mentioned (1) the study of the trajectories of air in travelling storms, embodied in an official publication entitled "The Life-history of Surface Air Currents"; (2) re-determination of the velocity equivalents of the Beaufort scale of wind force; (3) connection between the yield of wheat in eastern England and the rainfall of the previous autumn; and (4) possible relationship between exceptional strength of the south-east trade wind at St. Helena and exceptional rainfall in England. Reference to these investigations has already been made in our columns. We note that the payment hitherto made to Dr. Buchan, as inspector of stations in Scotland, is to

be continued for the time being in consideration of his important work in connection with the discussion of the results obtained at the Ben Nevis observatories. The complete or partial success of the weather predictions was very satisfactory during the year in question, e.g. harvest forecasts, 89 per cent.; forecasts appearing in morning newspapers, 88 per cent.; in both cases the best results were obtained in eastern and southern England. The number of storm-warning telegrams justified by subsequent gales or strong winds was 88.4 per cent. The committee points out that the service of storm warnings, which is extremely difficult on account of meteorological reasons, is aggravated by the frequent impossibility of getting telegrams delivered on the day of issue when dispatched in the evening or on Sundays, and it proposes to give this serious matter further consideration in the current year. The ordinary work of the marine and land branches has been much augmented by the reduction and tabulation of the observations of the National Antarctic Expedition and of auxiliary observations made in connection therewith, both at sea and on land, south of 30° S. latitude.

We have been looking rather carefully at the last published meteorological chart of the North Atlantic and Mediterranean for September, prepared by Commander Campbell Hepworth, marine superintendent of the Meteorological Office; one cannot help being struck with the almost crowded amount of information useful and interesting to seamen that it contains. Like its younger sister, the monthly chart for the Indian Ocean, the face is chiefly occupied by roses, showing for areas of 5° of latitude by 5° of longitude the frequency, direction, and average force of the winds; by waved arrows, showing the direction of Ocean currents and the maximum and minimum set in twenty-four hours; and by routes recommended for steam and sailing vessels respectively. The regions where fog is most prevalent are also shown, and the icebergs most recently observed along the Transatlantic steamer routes. The most southerly berg reported up to the early part of August was roughly in 45° N. 47° W., and the most easterly in 47° N. 40° W. On the back of the chart are given, inter alia, charts of tidal currents round the British Isles at the successive hours before and after high-water at Dover, and a co-tidal chart by Dr. Berghaus, with a useful explanation by Sir G. H. Darwin. As we are in the season of West India hurricanes, indications of their approach are explained and directions are given as to the most advisable steps to be taken when the centre of such a storm has been located.

The monthly meteorological chart of the North Atlantic for September, published by the Deutsche Seewarte, contains, generally speaking, similar useful information to that issued by the Meteorological Committee. The scale is somewhat larger than that of the English chart, and the wind-stars are printed in blue, the force, according to the Beaufort scale, being represented by feathers on the shafts of the arrows; altogether they form a prominent feature of the chart. The changes in the areas of high and low barometric pressure and other weather conditions shown graphically are also explained concisely in the text. On the back of the chart the true and magnetic bearings for a large number of points on the coasts when two lights or other objects are seen in line from the deck of a vessel afford an easy method of determining the deviation of the ship's compass. There are also small charts showing the mean isobars, isotherms, percentage of frequency of storms and calms for various localities in September, and the annual change in the magnetic declination. These pilot charts, brought as closely as possible up to the date of publication, are of the greatest practical value to seamen.

GEOGRAPHY AT THE BRITISH ASSOCIATION. IN his presidential address to Section E, Sir George

Goldie took the more or less obvious course of reviewing the progress of geography during the quarter of a century that had elapsed since the association last assembled in that city; but while necessarily saying something of the progress of exploration during that interval, he wisely passed rapidly over this side of the subject, and addressed himself chiefly to the wider aspects of the growth of the

scientific treatment of the subject and the spread of the geographical spirit among the people at large. The address was therefore unusually valuable from the point of view of all who are interested in the present position and future of the subject, both as an item in the educational curriculum of the country and as a study of undeniable importance to the general welfare of the nation.

There was a particular fitness in laying stress on this side of the question from the fact that, twenty-five years ago, as Sir George Goldie pointed out, a true conception of the functions and scope of geography was confined to a very limited circle of specialists, so that the progress 30 far made may be said to belong exclusively to the period under review. The investigation undertaken by the Roya. Geographical Society, which was undoubtedly the starting point of any success since achieved, was, in fact set in motion a few years after the previous York meer.ng of the association. The report issued by the society as result of Dr. Keltie's inquiries showed how entirely inadequate were the methods of geographical tuition in those days, and the little importance, with one or two praise. worthy exceptions, attached to it in educational circles The absurd prejudice" which, as then pointed out by one of the few more enlightened teachers, regarded th subject as unworthy of the attention of first-rate men, bas happily since been to a large extent overcome.

Sir George Goldie aptly diagnosed the source of car weakness as being, not the absence of the necessary can material, for few countries possessed a literature of trav and exploration so wide and of so high a class as our but the paucity of men qualified to apply scientific method to this raw material, and the want of an institution where a thorough training in geography might be obtained. H was able to point to the large measure of success which has attended the efforts of the Royal Geographical Societ and its coadjutors to remedy these defects, as evidenced in the present position of geography at Oxford and Cambridge and other of our universities. As a main cause vi a spread of interest in the subject among the people at large he assigned the marked re-awakening of the spir. of colonial expansion, from 1884 onwards, and held that empire-building is an even greater factor than war in advancing and popularising geographical knowledge."

As regards the future, he pointed out that though the popularity of a subject is by no means a test of its plac in the ranks of science, the democratisation of geographical ideas is a very hopeful feature, by reason of the widening of the area from which students can be drawn and men of genius evolved. In conclusion, he gave a by no means contemptible list of books and papers as samples of the work recently produced in this country under the stimulu of scientific method applied to geographical study.

Among the papers, discussions, and lectures which formed the remaining programme of the section, one by Mr. G. !! Hope, a young American professor from the Ohio State Normal College, may be first mentioned, on account of th close bearing which it had on the subject of the presidential address. In a valuable and suggestive paper Prof. Hope urged the importance of Social Geography as a subject o study which has hitherto been too much neglected. The paper well exemplified the wide field open to the studert of the new geography, and the need that it should t taken up by first-rate men if it is to lead to the moN! valuable results. The speaker dwelt, for instance, wide and thorough knowledge, not merely of geography in its narrower sense, but of allied subjects such as history technology, and economics, which is indispensable for s fruitful study of the problems of social distribution avowal that he had himself approached the subject largely under the inspiration of the geographical movement in thi country should give much encouragement to those who have worked so strenuously in its furtherance.

A large part of two mornings was taken up with well sustained discussions, one on coast erosion, the other i a proposal for improved geodetic measurements in Great Britain. The former was opened by a paper by Mr Clement Reid, F.R.S., who insisted on the net 1. approaching the subject with an adequate knowledge o past geological events in order to gain a comprehensiv grasp of all the factors. The erosion of our coast must be studied in conjunction with the deposition of the msters"!

eroded, and when this is done we find that the process has not continued regularly for an indefinite period, but began, as now manifested, only some 3000 or 4000 years go. In Neolithic times, according to evidence supplied by buried land surfaces, the sea stood 60 feet lower relatively to the land, and on the south and east coasts of England the rising downs were separated from the coasts by a wide plain. About 4000 years ago there set in a rapid but intermittent subsidence of the land or rise of the sea, on the completion of which the coast erosion now in operation began. In course of time shingle beaches and sand dunes were formed from the eroded material, and supply the best protection against further inroads. Much valuable alluvial land has also been formed in sheltered estuaries, so that it is an important question whether the net gain from protective works (if existent at all) would justify the enormous mutlay involved. In the discussion which followed (in which Prof. Percy Kendall, Mr. Whitaker, Mr. E. R. Matthews, and others took part) the need of taking a broad view of the whole question was again and again emphasised, instances being given of the detrimental results of uncoordinated protective operations. Mr. Matthews, an ⚫ngineer from Bridlington, gave some instructive details is to recent changes on the Yorkshire coast.

The geodetic discussion was opened by Major E. H. Hills, who pointed out that though the fundamental Triangulation of these islands was excellent work for the time at which it was done, it is now far behind the standard of modern work of its class. This is the more regrettable, inasmuch as it prevents the coordination of British with Continental work, although the necessary bservations to connect the two series have actually been made, and such coordination is of high importance in connection with questions such as the determination of the figure of the earth. All that is absolutely necessary is to connect geodetically, by as good a set of triangles as possible, the extreme points of our islands, and, were this done, amplitudes of 10° and 11° respectively would be added to two very important geodetic lines, viz. the meridional arc through the Greenwich meridian and the longitudinal arc along 52° N., which at present extend through 18 and 57°. Major Hills's proposals were warmly supported by Colonel D. A. Johnston (who presided at the discussion), Prof. H. H. Turner, Major Close (who mentioned as a less ambitious scheme the measurement of the central meridian of England running north from Southimpton), Colonel Hellard, director of the Ordnance Survey, and others, the small cost of the undertaking and the reproach to British science involved in the existing state of things being generally insisted on. At the close of the discussion Mr. E. A. Reeves described a new form of range-finder invented by him, which, though at present in an experimental stage only, gives promise of proving of great use in survey work as well as, possibly, for military purposes.

Several of the papers described the scientific results of recent expeditions. Mr. J. Stanley Gardiner, besides presenting the report on the general work of the Percy Sladen expedition in the Indian Ocean, described the Chagos Archipelago in detail, discussing the coral formations and touching also on the life conditions, especially of the vegetation. He showed that there was evidence here, as throughout the Indo-Pacific coral-reef region, of a relative rise in the land-level reaching from 5 feet to 35 feet, and probably due in great part to a withdrawal of water from the equator by the piling up of ice in the Antarctic. The atolls seem to have been formed on submerged shoals by coral and nullipore growth on the edges of the latter, and the lagoons show a progressive increase in depth and area through solution, boring and triturating organisms, and tides. Mr. R. N. Rudmose Brown described the South Orkneys and other localities in which scientific collections had been made by the Scottish Antarctic Expedition; Mr. J. Parkinson gave an outline of the physical structure of southern Nigeria a subject on which little has hitherto been known -from observations during a mineral survey of the region under the auspices of the Imperial Institute; and Mr. James Murray sketched the general scientific results of the survey of the Scottish lochs, discussing in particular the "internal seiche" which has been brought to light, and was explained as occurring on the cessation of a gale which

had maintained a temporary equilibrium between two bodies of water of different densities separated by an oblique line of separation.

Two papers dealt with the economic side of geography. That by Major Beacom, of the United States Legation, gave a most interesting account of the vast irrigation projects inaugurated within the past few years by the United States Government, enlarging in particular upon the Colorado River as the American Nile, and the changes in the Colorado desert due to irrigation. Prof. L. W. Lyde spoke of the wheat area in central Canada, showing how the climatic conditions favour the growth of that crop, especially along a line through Brandon and Battleford. He expressed a high opinion of the probable output of wheat from this area in the immediate future, but held that wheat growing was here eminently the work of the small farmer.

At the afternoon meetings illustrated lectures appealing to a more general audience than some of the above were given. Prof. W. M. Ramsay gave an instructive account of the past and present of Asiatic Turkey as influenced by physical conditions, tracing the fortunes of the region through their various vicissitudes, and forecasting a prosperous future from the advent of railway communication. Major P. M. Sykes described a tour in south-east Persia, dwelling on the many interesting historical associations and speaking of the ruined cities of the Narmáshir district. Mr. Yule Oldham interested a large audience with an account of the visit of the association to South Africa in 1905, while, lastly, Mr. Trevor-Battye showed a striking series of views illustrative of life and nature on the Zambezi above the falls, which he ascended at the close of the same visit of the association.

PHYSIOLOGY AT THE BRITISH
ASSOCIATION.

SEVERAL subjects of great practical importance were discussed at the Physiological Section of the British Association; so much was this the case that the section proved to be the resort of larger audiences than formerly, and before the end of the week the building placed at the disposal of Section I was all too small for its purpose.

Of the discussions, none was more appropriate to York than that introduced by Dr. F. Gowland Hopkins on the minimum proteid value in diet. This question has two aspects, the physiological and the sociological; the former was the subject of extended researches some time back under the guidance of Prof. Atwater and Dr. Benedict, and more recently under the very able superintendence of Prof. Chittenden at Yale. It is, however, the sociological aspect of the question which gives it an especial interest in York, for in that city, as is very generally known, Mr. B. Seebohm Rowntree has made a very laborious and complete investigation of the dietetic conditions which obtain amongst the poorer classes, and has convinced himself that about one-quarter of the whole population is insufficiently fed. The value of his research depends essentially upon a correct judgment as to the minimum diet upon which a labouring man can perform an efficient day's work. The sociologist is therefore dependent upon the physiologist for his fundamental data.

two

The physiological requirements of the body are fold-requirements of matter and requirements of energy; the necessary carbon and nitrogen must be provided, and they must be provided in a form which yields the number of calories equivalent to the energy dissipated The subject by the human organism as work and heat. was greatly simplified by Dr. Hopkins, for he showed that as the practical outcome of a large number of researches the energy value of the food might be almost disregarded. "It always worked out," he said, "that if the nitrogenvalue of the food was looked after the calorie-value would look after itself." Very different views obtain as to the minimum nitrogen value of a daily ration, and the disparity of view has been much increased within the last five years. We used to think that 100 grams of proteid food per day, giving 15 grams of nitrogen, was a somewhat restricted diet. Prof. Atwater has raised this figure considerably, whilst Prof. Chittenden has reduced it. Facilities have

been given to Prof. Chittenden and his colleagues by the American Government, and they have studied, not only themselves, but athletes in training and squads of soldiers, and have constantly found that by gradually accustoming these men to a carbohydrate diet a condition of physical efficiency and nitrogenous equilibrium can be obtained, though with some loss of weight. As the result of this gradual process the proteid might be reduced until only about 7 grams or grams of nitrogen were excreted daily.

Actual figures of nitrogenous output were given by Dr. J. M. Hamill and Mr. E. P. Poulton; the former with Dr. Schryver has investigated the nitrogenous output of the workers in the physiological laboratory of University College, London; the latter has experimented upon an Oxford student, aet. twenty-two, while he was going through the ordinary routine of university life at Oxford. There was great disparity amongst their figures. workers at University College varied from 8 grams to 16 grams of nitrogen daily, whilst Mr. Poulton's figure was a high one.

The

The low nitrogen values indicated above are of great scientific interest, but from the practical point of view they were shown to be of rather academic value by Dr. Hopkins. He made it quite clear that the observers who had obtained these values for the daily nitrogen output had done so on diets which were many times more expensive than those to which the working classes had access. He showed, in fact, that such food as a working man could buy must have a nitrogen value and a calorie value which was of the order indicated by Voit. The point at issue, then, between Dr. Hopkins and Mr. Rowntree was whether the moderate diet indicated by Voit or the more considerable one indicated by Atwater was to be taken as the basis of a proper daily allowance for the working classes. Now though there is a considerable difference between these two diets it is clear that there are lines along which a solution may be forthcoming. Three such directions were indicated by Dr. Hopkins :

(1) More searching analyses must be made into the nature of foodstuffs (and this point was developed by Prof. Armstrong). Maize, for instance, is particularly unsuitable as a staple dietary, not because it is of insufficient nitrogen value or even of insufficient calorie value, but because a particular kind of proteid, which is necessary to growth, is conspicuously absent from maize.

(2) The relative values of the various tissues as energy transformers must be attested. This work is being carried on by a committee of the British Association, and its annual reports for the past three years have been very instructive, but only the fringe of this large subject has been touched.

(3) Conditions of age and sex have not been thoroughly investigated. It seems clear that a developing individualsay of twenty years-requires a richer diet than a man of twice that age.

Dr. Hopkins readily conceded that even the trained athlete or the soldier might transform much less energy than was entailed in the daily toil of a bricklayer or a rivetter, and in view of this uncertainty we have some sympathy with Mr. Rowntree's contention that the calorie value demanded by Atwater, if acquired in the form of bad food eaten amid unappetising surroundings, was none too much for a heavy day's work.

"The

Another discussion of great interest, entitled Physiological Value of Rest, was introduced by Dr. Theodore Dyke Acland and Dr. Bevan Lewis. The former dealt chiefly with the hours of rest prescribed in the large public schools of this country. His views are so well known that it is not necessary to give them at length. The discussion was useful from several points of view, which may be briefly summarised :

(1) The necessity of obtaining scientific data concerning fatigue phenomena. This matter was dealt with by several of the pioneers in that branch of physiology, namely, psychophysics, which is rapidly springing up, and which bids fair to yield far-reaching results. Dr. Rivers, Prof. McDougall, and Dr. Myers indicated how the question might be approached on strictly scientific lines.

(2) The necessity for limiting the prevalent idea that "recreation is a change of occupation." This dictum is

useful and true so long as occupation does not amount to fatigue, but its utility ends at this point. When the system becomes fatigued, and this is especially true of the brain, the toxic bodies produced affect unused as well as used cells. It is futile to throw these cells, already prejudiced into activity. Such action simply adds to the amount of poisonous or toxic bodies in the circulation. This point was worked out with great clearness by Dr. Bevan Lewis, whose introductory address was on very different lines from that of Dr. Acland. Dr. Lewis treated the subject from a neurological, not a statistical, standpoint; he opened with a defence of the "* neuron theory," now assailed from so many quarters, and on this theory worked out a conception of the neurological basis of rest and of fatigue The practical outcome of his argument, as well as of De Acland's, was that physical exercise was no substitute for sleep, but that active physical exertion added to severe mental strain demanded a double meed of slumber. illustration of this point Dr. Aeland recounted how that Mr. C. B. Fry, at once a scholar and an athlete, frequently slept til midday or even late in the afternen during his school vacations, and in doing so gratifies nothing more than the healthy demand of his framephysical and mental-for rest.

In

(3) This discussion made clear the individual differences in the depth and time of slumber; thus day workers attain the maximum soundness of sleep early in the night, whilst night workers begin their slumber by sleeping somewhat lightly and sleep more soundly as morning approaches. Neurotic subjects, on the other hand, have two maxima on their sleep curve, one in the early part of the night, another in the morning; between these there is a period of shallow sleep. If any occurrence happens which causes a general reduction in depth of slumber, the period of shallow sleep in the middle of the night is replaced by a period of wakefulness.

(4) Prof. Gotch, who showed the utmost skill in weaving the separate items of this discussion into a contimum dwelt upon the nature of dreams as an index of the soureness of sleep. If a dream was a connected series of events and was recollected as such after waking, it was clear that the mental rest was impaired. The more coherent and the more realistic the dream, and the more directly it was roncerned with events in the recent past, the less restful was the sleep in which it occurred. The quality as well as the quantity of the sleep was all-important.

The sitting of Friday morning, August 3, was devoted to a paper on public health. Dr. George Reid, the medical officer of health for Staffordshire, put forward a number of telling arguments, the result of experiments which he had performed, in favour of changing the form of many sewage filters. It appears that the chemical changes which take place in a filter of fine partides ar completed relatively near the surface. Dr. Reid advocates the use of one-eighth inch particles, and of filters only abut 4 feet deep. Such filters would be much less expensiv than those now in use. A detailed account of his invest gations was recently published by the Royal Society.

Dr. Hime, of Bradford, brought forward a strong indictment of the present system of reporting and isolating infectious diseases. His data were collected from twentyfive large towns in the United Kingdom, and dealt with diphtheria, scarlatina, and typhoid, which taken together formed 95 per cent. of the cases reported. His general argument was that the epidemics of these diseases h increased in virulence and number within recent years in spite of the present system. The most telling figens which he adduced were from cases where the hospitais had been closed to one or other of these complaints and the cases sent back to their homes. On one such occasi m more than ninety cases of scarlatina were sent back to the poor neighbourhoods of a town. No epidemic tell al in fact, the epidemic which was prevalent ceased at once. The discussion which followed Dr. Hime's paper turned rather upon a matter of principle. Granted that exper® < were in doubt concerning the present system of reporting and isolating cases, was it wise to make the mater on of public discussion? Some medical officers held that sh debate weakened the trust in the public auther., 27 introduced an element of personal option as to whethe