to relegate the rare and occasional visitors-often of the utmost interest-to a future supplement, which will enhance the expense.

To the eye of an artist the plates will doubtless appeal as admirable specimens of the process employed, but to that of an ornithologist they lack the life and vigour which in many cases compensate for an absence of coloration.

Finally, we quite agree with Mr. Stonham that in many species the female and young are well worth depicting, and that it is quite useless to attempt to represent the songs of most birds by a set of syllables which each reader would in all probability mouth differently.

The Manufacture of Concrete Blocks, and their Use in Building Construction. By H. H. Rice and W. M. Torrance. Pp. 122. (London: Archibald Constable and Co., Ltd., 1906.) Price 8s. net. THIS work is a reprint in full of the two prize papers on concrete block construction in connection with a competition instituted by the Engineering News and the Cement Age, and, in addition, abstracts are given of the papers of ten other competitors, which contain data not given in the prize papers.

Mr. Rice in his paper deals fully with the raw materials—cement, sand and gravel, or crushed stone; with the mixing and manufacture of the blocks; and with the important questions of curing and facing the blocks with a finer quality of the material, and he briefly discusses the principles underlying the use of this material in building construction.

Mr. Torrance deals more fully with the form of the blocks, illustrations being given of many of the moulds for which patents have been granted, and with the relative cost of buildings of concrete and other material; finally, he states that from an artistic standpoint the best success so far obtained has been where the process of casting in sand has been adopted, and several reproductions of photographs are given to illustrate this point.

The abstracts of the other ten papers give much useful information on many points of detail not dealt with by the authors of the two prize papers, with regard both to the manufacture of the blocks and also to their employment in building construction.

In an appendix are the rules and regulations governing the use of this material and the testing of the blocks in Philadelphia. There has been quite a flood of literature during the past year on reinforced concrete, but until this book appeared little had been written in reference to the use of concrete by itself for building purposes.

net.

Elementary Electrical Calculations. By W. H. N. James and D. L. Sands. Pp. 216. (London: Longmans, Green and Co., 1905.) Price 3s. 6d. THIS book is based upon a series of lectures given by the authors to first- and second-year students of electrical engineering, and can be confidently recommended to those for whom it is written. So far as it goes, it is well arranged and perfectly clear; the only criticism that can be suggested is that it does not go far enough. The range of a subject which should be studied by first- and second-year students is, however, a matter for individual teachers to settle. It will suffice, therefore, to state that the book begins with an account of the fundamental units, proceeds to discuss Ohm's law very fully, and devotes brief chapters to power and work, conversion of energy, transmission and distribution treated quite simply, electrochemistry and photometry. Each chapter contains numerous examples fully worked out, and a large number of exercises for the student.

LETTERS TO THE EDITOR.

[The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of. rejected manuscripts intended for this or any other part of NATURE No notice is taken of anonymous communications.]

Biometry and Biology: A Rejoinder.

I SHOULD like to preface my remarks on Mr. Lister's reply by relieving his mind from any anxiety about Dr. Pearl's feelings. Dr. Pearl is in America, and I cannot, of course, communicate with him, but I know him intimately, and am convinced that he is far too good a man of science to feel aggrieved by any criticism of his writings. He might well feel aggrieved that Mr. Lister supposes him desirous that his paper should remain un criticised, because the criticism should affect his reputation. I am inclined to think that, as a fellow biometrician, he will rejoice with me that Mr. Lister's vague chargemade at a singularly unfitting moment-has been brought to a definite issue, and can be tried coram judice.

Had a first-year biometrical student in my laboratory sought advice from a biological freshman about the nature of Paramaecium caudatum, I should have anticipated that he would receive much the information with which Mr. Lister provides us. His remarks could only be made bị one who (a) had either not studied the memoir he criticises, or had failed to perceive the significance of the attempted accurate measurements on infusoria, or previously constants calculated by the author, and (b) had never to such attempt been trained to that caution and accuracy in measurement which it is the function of biometry to inculcate.

I challenged Mr. Lister to substantiate the charge he made in August, when, presumably, the grounds of his insinuation at York were fresh in his mind. He then considered that Dr. Pearl's position was traversed by the objection that the conjugants individually are possibly or probably differentiated gametes.

What was the author's position? He expresses it exactly by quotations from Huxley and Romanes :

"In my earliest criticisms of the Origin' I ventured to point out that its logical foundation was insecure so long as experiments in selective breeding had not produced varieties which were more or less infertile, and that insecurity remains up to the present time (Huxley, Life and Letters of Darwin," vol. i., p. 170).

"To state the case in the most general terms we may say that if the two basal principles are given in heredity and variability, the whole theory of organic evolution becomes neither more nor less than a theory of homogams --that is a theory of the causes which lead to discriminate isolation, or the breeding of like with like to the exclusion of unlike" (Romanes, Physiological Selection ''),

64

This problem of the divergence of individuals into varieties is the one selected by Dr. Pearl, and according to Mr. Lister is the best example by which he can illustrate his statement that biometricians do not select a soundi biological problem "before bringing a formidable mathe is the "hare cooked before it was caught," to cite again matical apparatus into action for its investigation." This Mr. Lister's phrase. Dr. Pearl shows that such homogam exists in an extraordinarily high degree in Paramaccium caudatum. In other words, he has broken entirely nov ground, which, to say the least of it, renders Huxley' position no longer tenable. This is now admitted, afte in a niggardly fashion, by Mr. Lister himself. In August he considered that Dr. Pearl's position was traversed br his omission to consider the differentiation of gametes which was possible or probable. He does not now ven endeavour to show that it is traversed by this, but say that I have claimed for Dr. Pearl the first demonstrat «un of the existence of this differentiation. In other words he now admits that Dr. Pearl has fully considered th problem of differentiation. In fact, more than hall Dr

Pearl's memoir is devoted to it. He further twits Dr Pearl and myself with not distinguishing between a man and his gamete !

from the conjugant, and only in the first days of the conjugating fit is there an approach to a very slight secondary mode at the conjugating type value. This may correspond in the first days to a very small percentage of individuals in a conjugating mood " among the non-conjugants. The skewness, however, as measured by Dr. Pearl's numbers, although slight, is the other way, showing that the non-conjugant population might best be conceived as a distribution wanting a portion about the conjugant type, and not as a population with an addition on that side, as it must be in the case of a mixture of non-conjugants and potential conjugants. Taking the variability of (a) all populations in which there were no conjugants, (b) populations of non-conjugants in which conjugants appear, and (c) populations entirely consisting of conjugants, we have the three numbers 8.7, 8.6, and 7-9, which suffice to show that non-conjugants in a conjugating population are practically identical in variability with non-conjugants in a non-conjugating population, i.e. the potential conjugate is a very small proportion of the population, conjugation taking place rapidly after the conjugating phase is reached. I am sorry to have to reply to Mr. Lister in this fashion. I fear, to use his own phrase, he will still " go away unedified from the biometric side of the church." But the time has come when vague insinuations based on no complete study of biometry must be replaced by some attempt to understand before criticism is passed. Above all, in a case like the present, a total disregard of the contents of Dr. Pearl's memoir and a suggestion that he has made errors and overlooked difficulties, which he has actually dealt with at every turn, is not to the credit of the critic. A man who has spent years in studying Paramæcia, and made thousands of measurements after much consideration of the difficulties, may reasonably expect a different type of criticism from another who clearly has attempted no such series of measurements, and whose authority for ex cathedra utterances may therefore be well called into question. Dr. Pearl's full paper is now in type, and I do not think his reputation will suffer when the paper is tested against the a priori criticisms which Mr. Lister has passed upon it. KARL PEARSON.

66

Biometric Laboratory, University College, London, October 12.

Radium and Geology.

IN NATURE of October 11 (p. 585) two letters appear on this subject, in reply to which a few words may perhaps usefully be said. Mr. Fisher's principal point is that if the earth's internal heat is maintained by radium, there is no room left for that shrinkage of the globe by cooling which some geological theories require. I think that the difficulty is only apparent. The duration of radium, it is generally agreed, is limited to a few thousand years. The supply must be in some way maintained, or there could be no radium on the earth now. Writers on radioactivity are generally agreed that the radium supply is kept up by the spontaneous change of uranium into radium.

Since radium is found in ordinary rocks, we must, on the received theory, suppose that uranium also exists in these rocks. It may be objected that uranium is never entered as one of the constituents found by chemical analysis. But, since the quantity to be expected is only of the order of 1/1000th of 1 per cent., this is not surprising. It might be possible, by very special methods, to detect uranium in granite, but I think in any case we may feel confident that it is there.

Everything depends on this initial supply of uranium. It gradually passes into radium, and, after that, into some inert form. The supply of uranium cannot last for ever. Its gradual diminution must involve the cooling and shrinkage of the globe.

It may perhaps be thought in these circumstances illegitimate to equate the escape of heat per second from the earth to the supply generated by radium in that time. There is reason, however, to feel pretty sure that thermal equilibrium is practically established in a time small in comparison with the duration of uranium, so that the rate of change in the amount of the latter can have no appreci- |

able influence on the distribution of temperature in the globe at any moment.

Mr. Palmer suggests that if the earth's internal heat is due to radium, the moon ought to be internally hot too, and its volcanoes should be active. I discussed the question of the moon's internal heat in my first paper (Proc. Roy. Soc., A, vol. lxxvii., p. 472). I quote from that paper" It has generally been supposed that the lunar volcanoes are extinct. But that view seems to rest chiefly on an a priori conviction that the moon has no internal heat. As Prof. W. H. Pickering has pointed out, all those observers who have made a special study of the moon have believed in the reality of changes occurring there."

Even if there were good reason to be sure that the lunar volcanoes were extinct, that would still be inconclusive. For it is believed by many geologists that volcanic action is due to the penetration of surface water to the hot interior of the globe. Thus volcanic inertness may be due, not to the absence of internal heat, but to the absence of surface water. R. J. SIRUTI.

The Rusting of Iron.

IN my remarks on "The Rusting of Iron," published in NATURE of September 27, I directed attention to the fact that pure hydrogen peroxide solution was rapidly decomposed by cast-iron, the latter becoming covered with rust. This, I stated, was, no doubt, due to catalytic action." In his friendly criticism of my remarks, Dr. Gerald T. Moody writes, in NATURE of October 4, that the metal becomes covered with rust in a few minutes, is not, however, to be referred to catalytic action, as Mr. Friend suggests, but is a consequence of the formation of acids by the oxidation of some of the impurities present in the iron, and of the subsequent electrolytic action."

That acids are formed in the above manner may be regarded as certain. These attack the iron, forming minute quantities of salts, which are decomposed by the oxygen of the peroxide, yielding rust, and liberating the acid, which can now attack more iron. In this way a small quantity of acid may be instrumental in oxidising a large quantity of iron. In other words, the acid is a catalyser, and the reaction is analogous to the rusting of pure iron in the presence of carbonic acid, oxygen, and water. The particular acid or acids which will cause this catalytic action must depend, of course, on the sample of iron used.

For the same reason "the intensity of action will be determined by the amount of acid formed on the surface of each particular sample of metal, when in contact with the peroxide." It is thus unnecessary to assume electrolytic action, as Dr. Moody suggests. This is sup ported by the fact that the same result may be obtained by employing pure iron, and commercial hydrogen peroxide which invariably contains hydrochloric acid and other impurities, as Dr. Moody has himself pointed out. Würzburg, October 9. J. NEWTON FRIEND

ETHNOLOGY OF SOUTHERN INDIA.1

mass of unfamiliar

THIS HIS book is a reproduction, with some additions and quotations from published materials, of the useful bulletins which the author, as curator of the Madras Museum and director of the Provincial Ethnographical Survey, has issued during recent years. The arrangement of the book might be much improved; full references to the authorities should have been given, while a bibliography would assist the student in investigating a literature. Even as it stands, the volume, with its useful collection of photographs, supplies much interesting material. The greater part of it is devoted to notes on marriage and death customs, and to a miscellaneous group of notes on omens, charms, magic, and the like. It is, as Mr. Thurston calls it, "a farrago," with which we can only deal by gleaning some of the interesting facts which abound in its pages.

FIG. 1.-Sorcery Figure. From "Ethnographic Notes in Southern India," by E. Thurston.

Thus in the notes on marriage we find the rite of confarreatio adopted by the Kammalans of Malabar in the case of polyandrous unions, a fact which we believe to be new to Indian ethnologists. The bride and her prospective bridegrooms, who are all brothers, are seated in a row, the eldest on the right, the others in order of seniority, and last of all the bride. The tribal priest solemnises the union by pouring milk into the mouths of all the parties to the contract. Much evidence on the subject of fraternal polyandry is here collected, but for a scientific treatment of the subject we must await the forthcoming book on the Todas by Dr. Rivers. Numerous cases, again, are given of actual or feigned resistance

are

as

offered by the friends of the bride to the bridegroom and his party. These accepted en bloc evidence of marriage by capture, which seems unscientific in view of the evidence collected by Mr. J. G. Frazer to show that many of these mock combats are really intended to promote the fertility of the soil, and are thus by analogy appropriated in the marriage rites. The hill people of Vizagapatam practise a curious method of selecting the bride. Near their houses is a pit in which the children are placed at night to keep them warm in the cold season. In spring all the marriageable girls are shut up in one of these pits, and a young man who has already selected his bride with the consent of his parents comes to the brink and sings out her name. If she likes him she comes out, a fire 1 "Ethnographic Notes in Southern India." By E. Thurston. Pp. vili+580; 40 plates. (Madras: Government Press, 1906.)

is lighted, and a dance solemnises the union. If she

sings back that she will not have him he immediately tries the name of another girl, and goes on doing so until he is successful.

The chapter on death rites, though badly arranged, abounds in useful information. Madras supplies an admirable field for such investigations, because prehistoric interments are numerous, and it would be interesting to compare the usages of the earlier people with those of the present forest tribes. This Mr. of facts will help European students to undertake the Thurston has not attempted to do, but his collection inquiry.

A good illustration of the theory propounded by Mr. E. S. Hartland at the York meeting of the British Association-that both magic and religion, in their earliest forms, are based on the conception of a transmissible personality, the Mana of the Melanesian races is found in the belief that from the eye of a man of low caste a subtle matter proceeds which contaminates food and other things upon which it falls. The most remarkable example of black magic

is found in the nude figure of a woman, with her feet turned backwards, a large square hole cut above the navel, and the whole body covered with long iron nails and Arabic inscriptions, which was washed ashore at Calicut in 1903. This figure, of which the illustration is here reproduced (Fig. 1), Mr. Thurston supposes to be that of a woman of the Laccadive Islands who was possessed by an evil spirit, "which was nailed to it before it was cast into the sea." The fact that the feet are turned backwards certainly indicates its demoniacal character, and it seems more probable that it represents some notorious witch; that the nails were driven into it and the mutilation made in order to injure her, and the spells added to destroy her magical power; finally, that the image was cast into the sea as a means of getting rid of the sorceress.

The chapter on fire walking supplies many facts, but does not help us much to understand the methods and significance of the rite. The question has been discussed by Mr. J. G. Frazer in his recent book on "Adonis, Attis, and Osiris," with the result that it

66

seems to be a survival of a rite of actual fire sacrifice. In some cases the juice of the Aloe indica is said to be used as a protective, but Mr. Thurston seems to believe that the indurated skin on the soles of men who habitually walk barefoot over the roughest ground accounts for many cases of immunity. A recent description by Mr. D'Penha of the rite as it is performed at Travancore indicates that the length of time which is allowed to expire between the lighting of the fire and the actual walking makes it an operation of little danger. Mr. Partridge, who witnessed the ceremony at Ganjam, describes the priest as going to the fire-pits, which were a mass of red-hot ashes; he sprinkled not more than a handful of incense on to them; dipped his feet in a mixture of rice-water and milk; and walked across one pit, leading another man. He then dipped his feet again in the fluid mixture, and returned by the other pit. The time he took in walking across one pit was not more than four seconds, and he took about four steps on the ashes. At least fifty persons in the crowd walked over the pits afterwards, but they went a little faster than the priest, and some of them only took two steps on the ashes. Their feet were not hurt, and they did not wash them in any mixture before or after they went over the ashes. I infer from the way in which the performance was conducted that anyone can easily walk over the ashes, but that, if he goes like the priest, he must dip his feet in the mixture both before and after walking across them." Mr. Risley, on the evidence from Bengal, came to the conclusion that when a narrow trench is used in the rite, it is possible for an active man to place his feet so rapidly on the edges of the trench that he does not actually touch the burning cinders, and escapes injury. Probably many performances of the rite may be explained in this way.

The chief ethnological curiosity of the museum is the Meriah sacrificial post from Ganjam, used in the blood sacrifices of the Khonds, of which the illustration is here reproduced (Fig. 2). It has suffered much damage from white ants, and its original form is not easily recognisable. It seems to represent the proboscis of an elephant to which the victim was bound. This, according to General Campbell, was one of the most common forms.

Mr. Thurston's book is arranged without any method, but it contains a mass of curious information which will make it welcome to European ethnologists.

IN

MEDICAL SCIENCE AND ARMY

EFFICIENCY.

N spite of the natural interest which the nation takes in the Army, few people realise completely what is the work that the Royal Army Medical Corps has to do, how vast are the responsibilities committed to it, and how dependent army efficiency is upon medical science. It is difficult to explain this want of interest and knowledge, but it arises probably from the fact that much of the work which the medical service does in the Army, both in peace and war, is of an unostentatious nature, and lacks the pomp and glamour which appeal so strongly to a public when associating itself with the military organisation of the country. Apart from this, the medical service suffered for many years under grave official disabilities, being systematically snubbed, and its professional and military pride injured. Such an attitude on the part of highly-placed persons in the military bureaucracy could not fail to dishearten its personnel and lessen any general enthusiasm or interest in its work by the general public. To a large extent these mistakes of

the past have been rectified, and the army medical service desires now, as it ever has done, to do its duty and to deserve well of the country; but it recognises that to do this it must advance and utilise fully the progress of science and the increasing knowledge of the profession of medicine which it represents in the military machine. Before attempting to explain these aspirations, it may not be uninteresting to readers of NATURE to sketch briefly the evolution of the army medical service from less enlightened times to the present day.

The need of medical attendance with an army in the field seems to have been always more or less recog nised. In the days of the early Edwards, physicians and surgeons are recorded as having formed part of the levies which were taken into the field; but until the sixteenth century the proportion of such men to the whole force was very small, and even in the time of James I. we find no allowance or provision in the estimates for medicines or hospital appliances; these details were supposed to be found by the surgeons themselves, for the cost of which a weekly stoppage of 2d. was made from the pay of the private soldier. It is not until the time of Marlborough that we find any sign of prominence being given to the medical service of the Army, but it was nearly fifty years later that the first reforms in military medicine and sanitation were introduced by Sir John Pringle, when physician-general to the forces in Flanders. The long series of wars in which England was engaged at the end of the eighteenth and the beginning of the nineteenth centuries produced many able men who left their mark on the organisation of the Army; not the least remarkable among them was Sir James M'Grigor, who, beginning his career as a military surgeon in 1793, became principal medical officer in Portugal and the Peninsula under Wellington, and finished his official career as medical director-general after the time of the great war. To him it was due that, in the service of which he was head, order was evolved out of chaos, and that the army medical service became an organised body, uniting in itself the best traditions of two professions.

In the long peace that followed Waterloo, our military machinery rusted from disuse or decay, notably the supplementary services which are necessary to form an army. The arrangements which had been made and the materials which had been collected in the old wartime for the care of the sick and wounded disappeared with nothing to replace them, and, when the Crimean War came, the best endeavours of the best men were powerless to grapple with the problems which were to be faced. The lessons of old experience had been for helpless, without means to carry out even an antigotten, and the army medical service found itself quated system of professional duty. At that time the army medical service consisted only of officers, divided into two classes, staff surgeons and regimental surgeons, though the whole were borne on one list, and, up to a certain rank, were interchangeabl, seniority he was promoted to be a staff surgeon of the After a regimental surgeon had attained a certain first class, and was employed thenceforth in superintendence and administration rather than in reci mental or personal professional practice. Practically all the officers of the medical staff had at one time or another been regimental surgeons, and presented in varying degree the merits or demerits of that training. The system of gazetting medical officers to individual corps had many advantages, both social and professionally, but it had undoubted drawbacks. The first and most important of these was that there than with their own corps, hence, if the public servic was a constant difficulty in utilising them elsewhere