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the phenomena of karyokinesis and their relation to fer In botany, twenty years ago, the teaching in our Unitilization will be reckoned hereafter as one of the most, if versities was practically sterile. In one of our earliest not the most, important of the biological discoveries of numbers, Prof. James Stewart defended with some vigour the past twenty years.
the propriety of intrusting botany to a lecturer at CamApart from Darwinism, the most remarkable deve bridge who was also charged with the duty of lecturing lopment of biological studies during these "twice ten on electricity and magnetism. It is startling to compare tedious years " is undoubtedly the sudden rise and a past, in which botany was regarded as a subject which gigantic progress of our knowledge of the Bacteria. might be tacked on anywhere, with its present condition, Though the foundations were laid fifty years ago by in which there is scarcely a seat of learning in the Schwann and Henle, and great advances were made three kingdoms which is not turning out serious work. by Pasteur and by Lister just before our period, yet The younger English school would be ungrateful if it it is within this span that the microscope and precise did not acknowledge its debt to the eminent German methods of culture have been applied to the study of the teachers from whom it has derived so much in the * vibrions," or " microbes,” and the so-called " bacterio- tradition and method of investigation. Sachs and De logy” established. We now know, through the labours Bary have left an indelible mark on our younger of Toussaint, Chauveau, Pasteur, and Koch, of a num- Professors. But it would be a mistake to suppose ber of diseases which are definitely caused by Bac- that English modern botany has simply derived from teria. We also have learnt from Pasteur how to control Germany. It has developed a character of its own, in the attack of some of these dangerous parasites. Within which the indirect influence of Darwin's later work can these twenty years the antiseptic surgery founded by be not indistinctly traced. There has been a gradual reSir Joseph Lister has received its full measure of volt in England, the ultimate consequences of which have trial and confirmation, whilst his opportunities and still to be developed, against the too physical conception those of his fellow-countrymen for making further dis- of the phenomena of plant life which has been prevalent covery of a like kind have been ignorantly destroyed by on the Continent. Darwin, by his researches on insectian Act of Parliament.
vorous plants and plant movements from a purely bioTo particularize some of the more striking zoological logical point of view, prepared the way for this ; Gardiscoveries which come within our twenty years, we may diner followed with a masterly demonstration of the cite--the Dipnoous fish-like creature Ceratodus of the physical continuity of protoplasm in plant tissues. This Queensland rivers, discovered by Krefft; the jumping has thrown a new light on the phenomena studied by wheel-animalcule Pedalion, of Hudson ; the development Darwin, and we need not, therefore, be surprised that and the anatomy of the archaic Arthropod Peripatus his son, F. Darwin, has started what is virtually a new worked out by Moseley, Balfour, and Sedgwick; the conception of the process of growth, by showing that its Hydrocorallinæ of Moseley, an entirely new group of controlling element is to be sought in the living protocompound animals; the fresh-water jelly-fish Limnoplasm of the cell, rather than in the investing cell-wall. codium of the Regent's Park lily-tank; the Silurian On the whole, English botanists have shown a marked scorpion of Gotland and Lanarkshire; the protozoon disposition to see in the study of protoplas the real key Chlamydomyxa discovered by Archer in the Irish bogs; to the interpretation of the phenomena of plant life. The the Odontornithes and the Dinocerata of the American complete analogy between the processes of secretion in palæontologists; the intracellular digestion obtaining animals and vegetables, established by Gardiner, and the in animals higher than Protozoa, and the significance of essential part played by ferments in vegetable nutrition, the " diapedesis " of blood-corpuscles in inflammation, and illustrated by Green, are examples of the results of this the general theory of phagocytes due to Mecznikow; the line of inquiry. To Germany we owe a flood of informaestablishment of the principle of degeneration as of equal tion as to the function of the cell-nucleus, which it is generality with that of progressive development, by Anton singular has met with general acceptance but little Dohrn ; the demonstration by Weismann and others that detailed corroboration in this country. we have no right to mix our Darwinism with Larmarckism, In morphology a review would be ineffective which did since no one has been able to bring forward a single case not go somewhat deeply into detail. The splendid hypoof the transmission of acquired characters. Perhaps the thesis of Schwendener, of the composite nature of lichens attempt to purify the Darwinian doctrine from Lamarckian as a commensal union of Algæ and Fungi, has gradually assumption will hereafter be regarded-whether it be won its way into acceptance. In England there is little successful or not-as the most characteristic feature of of the first rank which calls for note except the rebiological movement at the end of our double decade searches of Bower on the production of sexual organs on Its earlier portion was distinguished by the publication the leafy plant in ferns without the intervention of an of some of Darwin's later works. Its greatest event was intermediate generation. his death.
In vegetable physiology there seems a pause; the
purely physical line of inquiry, as already suggested, to the University Colleges throughout the country, of seems to have yielded its utmost. The more biological which last it is to be hoped that a fair proportion will be line of inquiry has only yet begun to yield a foretaste devoted to the promotion of research rather than to the of the results which will undoubtedly ultimately Aow reduction of class fees. from it.
Twenty years ago England was in the birth-throes of a Something must be added as to systematic and geo- national system of primary instruction. This year has graphical botany. The“ Genera Plantarum ” of Bentham seen the State recognition of the necessity of a secondary and Hooker, the work of a quarter of a century at Kew, and essentially a scientific system of education, and the affords a complete review of the higher vegetation of the Technical Instruction Act marks an era in the scientific world, and has been accepted generally as a standard annals of the nation. authority. To Bentham also we owe the completion of The extension of scientific teaching has gone on rapidly the “Flora Australiensis," the first complete account of the within and without our Universities. Twenty years ago flora of any great continent.
the Clarendon Laboratory at Oxford was approaching In geographical botany, perhaps the most interesting completion, and was the only laboratory in the country results have been the gradual elaboration of a theory as which was specially designed for physical work. Now, not to the distribution of plants in Africa, and the botanical only has Cambridge also its Cavendish Laboratory, but exploration of China, of the vegetable productions of both Universities have rebuilt their chemical laboratories. which, twenty years ago, almost nothing was known. both have erected buildings devoted to the study of biology.
In the classification of the lower plants, perhaps the and the instruction of students in both zoology and botany most interesting result has been the happy observations has taken a characteristic practical form which we owe of Lankester upon a coloured Bacterium, which enabled to the system of concentrating attention on a series of him to show that many forms previously believed to be selected" types” introduced by Rolleston and by Huxley. distinct might be phases of the same life-history.
Oxford has been furnished with an astronomical obserIn geology probably the greatest advance has been in vatory by the liberality of Warren De la Rue, and the application of the microscope to the investigation of Cambridge has accepted the noble gift of the Newall rock structure, which has given rise to a really rational telescope. Nor have such proofs of the vitality of science petrology. All except the coarser-grained rocks were been confined to the Universities. only capable of being described in vague terms; with Twenty years ago the Owens College was a unique modern methods their crystalline constituents are deter- institution: now, united with two thrivir.g Colleges in Leeds minable, however minute, and the conditions under which and Liverpool, it forms the Victoria University; while they were formed can be inferred.
science is studied in appropriate buildings in Birmingham, It is impossible, even in a brief review of this kind, Newcastle, Nottingham, and half a dozen towns beside. to think only of what has been won, and to ignore A race is thus springing up which has sufficient the loss of leaders who were once foremost in the fray. knowledge of science to enforce due recognition of its In England three names which will never be forgotten have importance, and public opinion can now, far more than it: been removed from the muster-roll. Darwin, Joule, and the past, be relied on to support its demands. Fortunately, Maxwell can hardly be at once replaced by successors of too, these can be authoritatively expressed. The Royal equal eminence. As the need arises, however, men will Society wields, if it chooses to exercise it, an enormous no doubt be found adequate to the emergency, and it is power for good. Admitted on all hands to be the suat least satisfactory to know that they will appeal to a preme scientific authority in this country, its decisions public more capable than heretofore of appreciating their are accepted with a deference which can spring only from efforts.
respect for the knowledge and scrupulous fairness by which The support afforded by the Governments of Western they are dictated. If sometimes it moves slowly, pur se Europe to scientific investigation has been markedly in- muove, and it is delightful to turn from the babble of the creased within the period which we survey. France has politicians to the study of an institution which does its largely extended her subsidies to scientific research, whilst work well, and perhaps too noiselessly. But even the Germany has made use of a large part of her increased House of Commons, hitherto ignorant and therefore apaImperial revenue to improve the arrangements for similar thetic in matters scientific, is awakening to the fact that objects existing in her Universities. The British Govern- there are forces to be reckoned with and impulses to ment has shown a decided inclination in the same direc- be stimulated and controlled which are of more endurtion: the grant to the Royal Society for the promotion of ing import to the national welfare than mere party scientific research has been increased from £1000 to politics. And the people, too, are beginning to see thar £4000 a year ; whilst subsidies have been voted to the it is to the economic working of these forces, and to Marine Laboratory at Plymouth, to the Committee on Solar the right direction of these impulses, that their repre Physics, to the Meteorological Council, and quite recently ! sentatives are bound to give attention. True it is that
another generation may possibly pass away before either of refraction ; so that a disk made of glass or other the House of Commons or even Ministers are sufficiently refracting substance, if set in rapid rotation about an instructed in science to recognize fully their responsibility axis through its centre, and at right angles to its plane, in this direction.
ought to act as if currents were circulating in the disk, Whatever, then, the future may bring, the last twenty avoid the allied difficulty that nothing has ever been
and produce a magnetic field around it. In order to years have been characterized by progress both steady observed which indicates that a magnet or a current and rapid. The tide flows on with no sign of check, flowing through a coil possesses gyroscopic properties, and we accept the success of NATURE in no spirit of Prof. Lodge assumes, in subsequent chapters, that the self-gratulation, but as a straw by which the speed of the Auid in the cells of the ether is a mixture of two fluids, current may be gauged.
and that these two Auids are positive and negative electricity: ard that, in order to exhibit any electrical effect,
the compound fluid has first to be decomposed into posiMODERN VIEWS OF ELECTRICITY.
tive and negative electricity by the application of an Modern Views of Electricity. By Oliver J. Lodge, D.Sc., electromotive force. A current of electricity, on this view,
LL.D, F.R.S. (London: Macmillan and Co., 1889.) consists of the flow of equal quantities of positive and IN N this interesting book Prof. Lodge gives a very lively negative electricity in opposite directions. Thus this, the
and graphic account of many of the most recent most "modern view of electricity," is in its most imspeculations about the nature of electrical phenomena. portant features almost identical with the old two-fluid A work with this object was urgently needed, as the theory published by Symmer in 1759. We confess we do method of regarding these phenomena given in popular not think the theory in its present form advances the treatises on electricity is totally different from that used science of electricity much: it does not suggest new pheby those engaged in developing the subject.
nomena, nor does it lend itself readily to explain the The attention called by Faraday and Maxwell to the action of matter in modifying electrical phenomena ; it effects produced by and in the medium separating electri- demands, too, a very artificial ether. It would seem that fied bodies has had the effect of diverting attention from the first steps required to make a theory of this kind a the condition of the charged bodies in the electric field real advance on the old two-fluid theory would be the disto that of the medium separating them, and it is perhaps covery of a structure for the ether, which would possess open to question whether this of late years has not been the same kind of properties as the mixture of the two too much the case. To explain the effects observed in electricities on that theory. A great deal, too, is left the electric field we should require to know the condition indefinite in the theory: thus, for example, we are not not only of the ether, but also of the conductors and in- told whether for a given current these streams are moving sulators present in it; just as a compiete theory of light slowly or with prodigious velocities. would include the state of the luminous bodies as well as throughout the book rather a want of definite conclusions, of the ether transmitting the radiations excited by them. and this is rather hidden by the vigorous style in which Since matter is more amenable to experiment than the Prof. Lodge writes : he develops his ideas in such an ether, it seems most probable that we shall first gain an enthusiastic and interesting way that on the first reading insight into the nature of electricity from a study of they seem to be a good deal more definite than they prove those cases where matter seems to play the chief part, to be on calmer reflection. such as in the electric discharge through gases, and
But whatever may be thought of Prof. Lodge's theory the phenomena of electrolysis—rather than from specula- of electricity, there can be, we think, no two opinions of tions, however interesting, as to what takes place in the the value of the numerous models illustrating the properether when it is transmitting electrical vibrations. Prof. ties of electrical systems which he has invented. These Lodge, however, in the work under consideration, devotes must prove of the greatest assistance in enabling the most of his space to the consideration of the ether. In student to gain a clear and vivid idea of electrical prohis preface he says, "Few things in physical science cesses, and ought to be largely employed by all teachers appear to me more certain than that what has so long of electricity. been called electricity is a form, or rather a mode, of
In a work dealing so briefly with such a multitude of manifestation of the ether;” and be proceeds to give different and difficult subjects it is natural that there precision to this somewhat vague statement by developing should be many statements to which exception might be a theory that electricity is a fluid, and a constituent of a taken. Prof. Lodge disarms criticism by his frank advery complex ether. In the first few chapters he sup- mission of this ; sometimes, also, by an amusing vagueness poses that all insulators, including the ether, have a of statement : thus, on p. 296, in speaking of the condicellular structure the cells being filled with a fluid which tion of the ether inside a strongly-magnetizable substance, 15 electricity, and which is not able to get from one cell he says: "Perhaps it is that the atoms themselves revolve to another unless the walls of the cells are broken down ; with the electricity ; perhaps it is something quite differin conductors, however, there are channels between the ent.” There are, however, some statements of a less cells, so that the electricity is able to flow more or less theoretical kind which seem to us likely to mislead the freely through them. A flow of this fluid is an electric student. Thus it is stated that the amount of the Peltier current. But if this is the case, anything which sets the effect shows that the difference of potential between zinc ether in motion will produce an electric current. Now, and copper is only a few micro-volts. The Peltier effect, Fizeau's experiments show that moving bodies carry the however, without further assumption, cannot tell us any. ether with them to an extent depending on their index thing about the absolute magnitude of the difference of
potential between the metals ; it can only give us the causes” of an observed event, or the ways in which : value of the temperature coefficient, which is equal to the might have happened, by means of the calculus of protPeltier effect divided by the absolute temperature. Then, abilities, it is usual to make certain unwarranted assumpagain, the pyro-electricity of tourmaline is explained by tions concerning the so-called a priori probability of those the unilateral conductivity of a tourmaline crystal whose causes. Suppose that a number of black and white balls temperature is changing, discovered by the author and have been drawn at random from an urn, and from thu Prof. Silvanus Thompson. If this unilateral conduc-' datum let us seek to determine the proportion of blaci tivity is regarded as proving the existence of an electro-, and white balls in the urn. It is usual to assume, withou: motive force in a crystal which is increasing or decreasing sufficient grounds, that a priori one proportion of balls. in temperature, the explanation is valid, but in the text one constitution of the urn, is as likely as another. Or nothing is said about an electromotive force, and the suppose a coin has been tossed up a number of times, and student might be led to infer that a mere difference in from the observed proportion of heads and tails let ir be resistance could explain pyro-electricity. The way in ' required to determine whether and in what degree the which a current flows past an insulating obstacle, the lines' coin is loaded. Some assumption must be made as to of flow closing in on the obstacle, and leaving nothing the probability which, prior to, or abstracting from, ou corresponding to "dead water” behind it, is given as a observations, attaches to different degrees of loading. The proof that the electric current has no mechanical mo- assumptions which are usually made have a fallacious mentum ; but unless the corners of the obstacle were character of precision. infinitely sharp, a slowly-moving fluid might flow in the Again, M. Bertrand points out that the analogy of urns same way as electricity, even though it possessed inertia, and dice has been employed somewhat recklessly by so that the proof is not conclusive. It is also stated that Laplace and Poisson. It is true that the ratio of male to the effects on light produced by a magnetized body, dis- female births has a constancy such as the statistics : covered by Dr. Kerr, of Glasgow, have been deduced by games of chance present. But, before we compare bors Prof. Fitzgerald from Maxwell's theory of light. As a ' and girls to black and white balls taken out at random matter of fact, however, the results deduced from this from an urn, we must attend not only to the average protheory by Fitzgerald do not coincide with those observed portion of male to female births, but also to the deviations by Dr. Kerr and Prof. Kundt. The production in an from that average which from time to time or from place unequally-heated conductor of an electromotive force is to place may be observed. The analogy of urns and balls explained by supposing the atoms in such a body to be is more decidedly inappropriate when it is applied to moving faster in one direction than the opposite, and determine the probable correctness of judicial decisions therefore, since they are supposed to drag the ether with | The independence of the judges or jurymen which the them, producing a flow of ether in the direction in which theory supposes does not exist. they are moving fastest ; but, on the dualistic theory of electricity adopted in this book, this ether stream would il n'a pas réellement mis la main dans une urne où le
“Quand un juge se trompe il y a pour cela des raisons consist of equal quantities of positive and negative elec- hazard' l'a mal servi. Il a ajouté foi à une faux tétricity moving in the same direction, and this would not moignage, le concours fortuit de plusieurs circonstances a produce any electrical effect.
éveillé à tort sa défiance, un avocat trop habile l'a ému. At the end of the book are three popular lectures de. de hautes influences peutêtre l'ont ébranlé. Ses collègues livered by Prof. Lodge, the first on the relation between ont entendu les mêmes témoins, on les a instraits des electricity and light , the second on the ether and its eux, on a tenté sur eux la mêne pression."
mêmes circonstances, le même avocat a plaidé devant functions, and the third his admirable one at the Royal Institution, on the discharge of a Leyden jar, which is a With equal force does M. Bertrand expose the futility model of what such a lecture ought to be.
of the received reasoning by which it is pretended to deterTaken as a whole, we think that the book is one which mine the probability that the sun will rise to-morrow from ought to be read by all advanced students of electricity; the fact that it has risen so many days in the past. they will get from it many of the views which are guiding These reflections are just and important; but their those who are endeavouring to advance that science, and value is somewhat diminished by the fact that they have it is so stimulating that no one can read it without being been, for the most part, made by previous writers with inspired with a desire to work at the subject to which it whom our author seems unacquainted. Thus Prot. is devoted.
| Lexis has more carefully considered the extent of the | error committed by Laplace and Poisson in applying to
male and female births and other statistics rules derived THE CALCULU'S OF PROBABILITIES. from games of chance. The fundamental principles of
Probabilities have been more fully explored by Dr. l'enn. Calcul des P'robabilités. Par J. Bertrand. (Paris: M. Bertrand, like Laplace, starts by defining the probGauthier-Villars, 1889.)
ability of an event as the ratio of the number of favour“Έ'
VERYBODY makes errors in Probabilities at times, able cases to the number of possible cases. He does not
and big ones," writes De Morgan to Sir William explain what constitutes a "favourable case”-that, when Hamilton. M. Bertrand appears to form an exception a die is thrown, the probability of obtaining the 3 or to this dictum, or at least to its severer clause. He 4 is one-sixth, because as a matter of fact each side in avoids those slips in the philosophical part of the subject the long run turns up once out of six times. Accordingly. into which the greatest of his mathematical predecessors when he argues that in a great number of trials each have fallen. Thus he points out that, in investigating the event is most likely to occur with a frequency correspond
ing to its probability, he lays himself open to the charge whom this argument may be derived, has not himself of circularity which Dr. Venn has brought against Ber- used it very directly. But in a writer on the method of nouilli's theorem. Without pronouncing on this delicate least squares we may expect some conversance with more question, we may safely say, with respect to the first recent works, in particular with Mr. Glaisher's classical principles of the subject, that no point which has been paper in the Memoirs of the Astronomical Society left obscure by Dr. Venn has been cleared up by M. (London). Moreover, Laplace does employ the matheBertrand.
matical theorem which we have indicated, not indeed to It is with respect to the purely mathematical portion of prove that the law of facility for errors of observation in the calculus, or that part of its metaphysics which is general is the probability-curve, but that, whatever that inextricably mixed with mathematics, that we expected | law of facility be, the most advantageous combination is a and have found most assistance from M. Bertrand. certain linear function. A treatise in which this celebrated Hitherto the study of Probabilities has been barred by argument is not discussed cannot be regarded as exhaustthe dilemma which M. Bertrand thus states :
ive. But it is remarkable that with respect to the com« On ne peut bien connaître le calcul des probabilités bination of observations, M. Bertrand seems to defer sans avoir lu le livre de Laplace; on ne peut lire le livre more to Gauss than to his own eminent countryman. de Laplace sans s'y préparer par les études mathématiques M. Bertrand has indeed slipped in a doctrine for which les plus profondes."
the authority of Laplace may be quoted, that in choosing Much of Laplace's analysis which must have affected the best combination of a set of observations " there is many eager students like stickjaw has been simplified an essential difference between the most probable by M. Bertrand. He is in general more readable than value of a quantity and the value which it is best to Poisson. Several of the theorems which he gives seem adopt” (Bertrand, Art. 138); the latter being the mean to be new. His methods of determining from a given set (first power) of the observations (Art. 155)—which M. of observations the characteristic, or modulus, appertain. Bertrand rather awkwardly terms "la valeur probable." ing to the source of error are specially interesting.
M. Bertrand does not seem to realize the gravity of the M. Bertrand's mathematical power enables him to carry assumption which is contained in the latter clause. Later the torch of common-sense to those perplexed parts of the on he employs Gauss's criterion of erroneousness-namely, subject where less qualified critics, awed by the imposing the mean square of error. But the ground, nature, and mass of symbols, have hesitated to differ from Laplace or relation of these two principles are not very clearly Poisson. Of this kind is the simultaneous determination explained by the writer. With respect to the philosophical of several quantities from a great number of equations. foundation of the method of least squares he has not When Laplace computes that the odds are a million to superseded the necessity of studying Laplace. one against the occurrence of an error of assigned magni
With these reservations, M. Bertrand's work may be tude in the determination of Jupiter's mass, M. Bertrand regarded as one of the most complete treatises on the shows reasons for suspecting the accuracy of such com- subject. Nowhere else are the two elements so pecuputations. In fact, he carries out Poinsot's witty direction : liarly combined in the science of Probabilities--common" Après avoir calculé la probabilité d'une erreur il sense and mathematical reasoning-to be found existing
F. Y. E. faudrait calculer la probabilité d'une erreur dans le together in such abundance. calcul."
The true import and proper application of the theory of errors of observation are thus well expressed :
ARGENTINE OR WITHOLOGY. “On peut accepter sans crainte le résultat, mais il est Argentine Ornithology. By P. L. Sclater, Ph.D., F.R.S. téméraire d'évaluer en chiffres la confiance qu'il doit and W. H. Hudson, C.M.Z.S. Vol. II. (London: W. inspirer."
H. Porter, 1889.) u Bertrand teaches with hauthority and not like those The completion of this important workoise an event ings of the calculus-in what spirit its conclusions should tropical zoology, and the authors have both performed be accepted.
their parts well, while the ten plates by Mr. Keulemans Still, even with regard to those parts of the subject are beautifully drawn and admirably coloured. Among where a first-rate mathematician has so great an advant- the increasing number of Englishmen who settle in the age, we venture to think that the work would have been Argentine Republic, there are sure to be many who will much more valuable if the writer had taken the trouble to pursue natural history studies, and to all such a well-exeacquaint himself more fully with what his predecessors cuted book like the present will be invaluable. The joint had done. For example, in discussing the reasons for taking authors of the work are happy in their association, for the arithmetic mean of a set of observations (presumed to while Dr. Sclater brings to the work a vast experience, be equally good) relating to a single quantity, M. Bertrand and a sound scientific knowledge of his subject, it is does not dwell on the argument that the probability-curve certain that never was there a better describer of the -with which the arithmetic mean is specially corre- habits of birds than Mr. Hudson. Although of English lated—is apt to represent the grouping of errors for this parentage, he is a native-born Argentine, and he has reason, that an error may be regarded as a function of a grown up among the birds whose life and history he so great number of elements each obeying some definite law well knows how to portray. In turning over the pages of facility, and that the values of such a function conform of this volume, we have found many interesting extracts to the probability-curve. It is true that Laplace, from which we should have liked to present to our readers,