12) Although physiological selection must in all cases refer primarily to first crosses, its activity as a cause of segregation is intensified in cases where it extends also to second crosses.

eux.

SCIENTIFIC SERIALS.

American Journal of Mathematics, vol. xii., No. 3 (Baltimore, March 1890.)—A memoir "Sur les équations aux dérivées partielles de la physique mathématique," by that brilliant mathematician, M. Poincaré, occupies pp. 211-294. Some idea of the writer's aim will be gained from the following passages: "Quand on envisage les divers problemes de calcul integral qui se posent naturellement lorsqu'on veut approfondir les parties les plus différentes de la physique, il est impossible de n'être pas frappe des analogies que tous ces problèmes présentent entre "Cette revue rapide des diverses parties de la physique mathematique nous a convaincus que tous ces problèmes, malgre extreme variété des conditions aux limites, et même des équations différentielles, ont, pour ainsi dire, un certain air de famille qu'il est impossible de méconnaître. On doit donc s'attendre à leur trouver un tres grand nombre de propriétés communes.' The concluding sentence is: "Je pourrai dire alors que les conclusions sont démontrées d'une façon rigoureuse au point de vue physique. Peut être même est-il permis d'espérer que, par une sorte de passage à la limite, on pourra fonder sur ces principes une demonstration rigoureuse même au point de vue analytique." The remaining article of the number is one on singular solutions of ordinary differential equations, by H. B. Fine (pp. 345-322). Following the lead of Briot and Bouquet, this memoir hases the theory of singular solutions on the differential equation, and avoids all use, direct or indirect, of the notion of the complete primitive.

1x Bulletin No. 2 of the Brussels Academy of Science, M. E. Ronkar criticizes a paper by M. J. Liagre, on the mutual mpulse of the earth's surface and centre because of interior friction. The paper in question dealt with the interior structure of the earth, and the conclusions drawn have some bearing on diurnal nutation. In a paper on the venous pulse, M. Léon Fredericq gives his investigations into the form of various pulses -jugular, venous, and carotid; traces the identity of the pulse of The jugular vein and that of the right auricle; and discusses generally the phenomena of circulation and respiration. The same author adds a note on the preservation of oxyhemoglobin. -M. A. F. Renard has examined phillipsite crystals from the deposits obtained from the centre of the Pacific Ocean. These microscopical crystals were discovered by Mr. Murray, and a nef description of them published by him in conjunction with the author in 1884 (Royal Society of Edinburgh). A more particular description and determination of the character of these zeolites, and the deposits in which they occur, is now given. A plate containing four drawings of the crystals accompanies the! paper.-M. G. van der Mensbrugghe, in a paper on the condensation of water-vapour in capillary spaces, reviews the rincipal facts owing their origin to such condensation, and shows that they are in confirmation of the theory propounded by Sir William Thomson in 1874, in a paper on the equilibrium of vapour at a curved surface of liquid. The experimental verification of the formula there given will form the subject of

a second communication.

SOCIETIES AND ACADEMIES.
LONDON.

Royal Society, February 20.-"Some Stages in the Development of the Brain of Clupea harengus." By Ernest W. L. Holt, Marine Laboratory, St. Andrews. Communicated by Prof. McIntosh, F.R.S.

The stages described are (i) newly-hatched or carly larval; (ii) early post-larval; (iii) inch long; (iv) inch long.

The development of the pineal region is treated separately, and in this a fifth stage-1 inch long-is introduced.

In the early larval stage the downward flexure of the fore part of the brain is very noticeable. It appears due to the general conformation of the head at this stage. A diverticulum of the 3rd ventricle extends downwards and backwards, its distal extremity underlying the optic commissure. The broad ventral

commissure of the infundibulum, noticed by McIntosh and A commissure shuts off Prince in Anarrhicas, is well marked. the lumen of the infundibulum from the hind part of the 3rd ventricle immediately in front of the splitting off of the infundi bulum. The valvula appears in transverse section as a pair of ridges externally to the tori, before it shuts off the aqueduct of Sylvius. The cerebellar fold is very short.

In the early post-larval stage "an apparent rectification of the cranial axis" has taken place, by the upward rotation of the cerebrum on its posterior end, doubtless owing to the rapid development of the oral and trabecular cartilages, and consequent forward rotation of the mouth. The same causes have also operated so as to withdraw the diverticulum of the 3rd ventricle from its position below the optic commissure. The infundibulum has undergone vertical flattening. The future lobi inferiores are indicated as lateral expansions, behind which the 3rd oculomotor nerves pass outwards from the centre of the ventral surface of the cerebral mass. The infundibulum extends some way back above the notochord as a thin-walled sac. Its walls are little plicated compared with those in some other forms, e.g., Rhombus,

Anarrhicas.

In the inch stage the olfactory lobes appear as bulbous masses projecting from the front end of the cerebrum. A pale median septum appears between the anterior extremities of the lateral optic ventricles, its base resting on the fibrous tract over the hind part of the 3rd ventricle. The tip of the valvula now appears in transverse section before its connection with the cerebral mass can be made out, having thus grown forward. The cerebellum has greatly increased in size; instead of terminating as before on the surface of the brain, it is now continued into a thick fold bent sharply down on the anterior portion; its posterior end passes at once into the thin roof of the 4th ventricle. Two fibrous bands cross over the aqueduct of Sylvius in the substance of the cerebellum; their lateral extremities are fused. The lobi inferiores are better marked than in earlier stages. Longitudinal bands of fibres pass back from the roots of the oculomotor nerves through the medulla oblongata. Groups of large ganglionic cells appear on either side of these bands, and are connected by a fine commissure passing through both bands. At the origin of the 8th auditory nerves, this commissure is replaced by a St. Andrew's cross of fibres, the dorsal limbs of the cross passing to the nerve roots, and the ventral to the ganglionic areas.

In the -inch stage the olfactory lobes are more elongated. The olfactory nerves pass outwards from their anterior extremities. The septum behind the pineal body, after losing its ventral connection with the fibrous tract over the 3rd ventricle, persists for some way back as a cellular leaf-like appendage of the thin median roof of the optic ventricle; a few fibres pass back into this appendage.

Large ganglionic cells appear in the tori semicirculares about the region of the splitting off of the infundibulum.

From behind the region of the auditory nerves a ganglionic area on either side persists backwards through the medulla oblongata.

Pineal Region.

The roof of the thalamencephalon in the early stages is a single layer of large columnar cells passing forward from the front wall of the pineal stalk. It passes into the roof of the cerebrum, the cells diminishing greatly in size. The superior commissure of Osborn is present from the early post-larval stage; it it also present in the larval and post-larval Zoarces viviparus, where it is distinctly double. The first signs of the infrapineal recess of Hoffman are seen in the 4-inch stage. It is thus much later in developing than in Salmo, and the fold forming its front wall never extends backwards to the same degree as in that form and in Anarrhicas. This fold, in the post-larval Zoarces, is thickened in its apex, and lodges a fine commissure. As pointed out by Balfour in Elasmobranchs the fold is due to the upward rotation of the cerebrum.

The fibrous tract over the 3rd ventricle in the herring is well marked in the -inch stage. It is seen to consist of fibres passing upwards and inwards from the optic thalami to the middle line above the 3rd ventricle, and then running forward to the stalk of the pineal body. The tract has a double nature, as is readily seen in vertical longitudinal sections of a herring 1 inch long. It is seen here to be a backwardly directed fold of the brain roof, continuous ventrally with the back wall of the pineal stalk, and dorsally with the roof of the optic ventricle, the apex of the fold being the posterior commissure. Its length in this form is due to the flattening of the brain, the tract being very stort in

Zoarces, where the brain is not flattened. In Zoarces, also, from the same cause, the limbs of the fold are less closely applied to each other and much thicker.

The pineal body is roundish and solid in the early larval stage in the herring. It is vertically flattened in the early post-larval stage. In the -inch stage it is much larger and contains a lumen; it shows signs of constriction into proximal and distal elements, and the lumen contains a coagulable albuminous fluid, as in Petromyzon. In the 1-inch stage the constriction is still visible, and the walls are generally crenated. The tissues of the pineal wall are now divided into three layers, and are of varying thickness. The cartilage of the tegumen cranii overlies the body at this stage. The constriction of the body appears to be an exaggeration of the crenation of the pineal wall met with in Salmo; it has not, probably, the morphological value of the constriction of the body in Petromyzon.

March 27-On the Stability of a Rotating Spheroid of Perfect Liquid." By G. H. Bryan. Communicated by Prof. G. H. Darwin.

66

The investigations of Riemann, Basset, and others have proved that Maclaurin's spheroid, when composed of frictionless liquid, ceases to be stable for an ellipsoidal" type of disturbance when its eccentricity attains the value 019528867. The object of the present paper is to discuss the conditions of Stability with reference to disturbances of a general type expressible in terms of spheroidal harmonics, with the view of examining whether Riemann's condition is sufficient to ensure stability for displacements other than ellipsoidal.

Taking the criteria of stability determined in a previous communication (Phil. Trans., A., 1889), the author shows by numerical calculation that the form which is critical for an ellipsoidal disturbance is stable for disturbances determined by several of the lower harmonics. These results are then extended by a perfectly general investigation to all other types of displacement.

The conclusion is that Riemann's and Basset's condition of stability is sufficient to ensure the absolute stability of Maclaurin's rotating spheroid for every possible displacement. Also that, unless the liquid is subject to hypothetical constraints, we cannot initially obtain any form other than ellipsoidal from the instability of the spheroidal form. In the case considered of perfect liquid this ellipsoid does not rotate as if rigid, but its principal axes rotate with half the angular velocity of the liquid.

Physical Society, March 7. -Prof. W. E. Ayrton, F. R. S., President, in the chair.-Dr. S. P. Thompson described Bertrand's refractometer, and exhibited the capabilities of the instrument before the Society. Its action depends on total reflection. The refractometer consists of a hemisphere of glass, about 8 mm. diameter, set at the end of a tube, the plane face being outwards and inclined at about 30° with the axis. One side of the convex surface of the hemisphere is illuminated through a piece of ground glass set about perpendicular to the plane face. The hemisphere is viewed through an eye-piece focussed on a scale divided to tenths of millimetres placed within the tube. The instrument is particularly useful for mineralogical specimen and liquids. The procedure in the latter case is to smear a film of the liquid over the plane face of the hemisphere, and by looking through the eye-piece determine the scale reading of the line which separates the light and darker portions of the field. A reference to a calibration table gives the refractive index. In experimenting with solids a thin film of a very dense liquid (supplied with the instrument) is placed between the specimen and the glass, and the procedure is then as above. The refractive index of opaque solids can be determined in this way. In using the instrument for minerals great care must be taken not to scratch the glass. The handiness of the refractometer and its perfect portability (its dimensions being about 5 centimetres long by 24 cm. diameter) are great recommendations. Mr. Blakesley asked to what accuracy the scale could be read, and whether the sensitiveness of the instrument was at all comparable with that of other methods. Prof. Dunstan inquired if it could be used with volatile liquids. In reply Dr. Thompson said that with non-homogeneous light the scale could be read to 1 division, but with a sodium flame one-tenth of a divi-ion could be estimated. For volatile liquids, a drop may be used instead of a film, or the evaporation of a thick film may be retarded by a cover-glass.-Mr. H. Tomlinson's paper, on the Villari critical point in nickel, was postponed.-Prof. Dunstan described an apparatus for distilling mercury in a

vacuum, devised by himself and W. Dymond, and showed the working of the arrangement. It consists of a 3 mm. soft glass tube rather more than a metre long, having an oblate spheroida bulb blown at the upper end. The bulb is placed over a rit burner. At the top of the bulb, a tube of 15 mm. diameter attached, and this passes outside the bulb, and descende close the larger tube. The part of the smaller or fall tube just below the bulb is enlarged so as to form a condensation chamber, and the lower part serves as a Sprengel tube. A conical reservoir containing the mercury to be distilled is in flexible connecura with the lower end of the large tube as in Clark's well-known apparatus. The advantages claimed for the new apparatus tt. its relative shortness and portability, the small quantity rema ing undistilled, and its non-liability to damage or derangement v left unsupplied with mercury. To ensure satisfactory working a constant pressure of gas is necessary, and this is obtained o inserting a Sugg's dry governor in the supply pipe. Daneg distillation, peculiar green flashes are seen within the condens tion chamber, and these are intensified by bringing it near an electric machine in action. The apparatus also serves well t show the character of an electric discharge through mercury vapour, for the mercury in the two tubes may be used as elec trodes. Prof. Thompson said he devised a simple form of distilling apparatus some time ago which answered fairly wel of a double barometer, one leg of which was of small bors. and could be made by any amateur glass-worker. It cons stei as to act as a Sprengel tube. The rising part of the bend at the top of the larger tube was expanded and served as the evaporz ing chamber, below which a burner was placed. The Presiden asked why Clark's apparatus is made so lengthy. In reply ty this question Mr. Boys said that as the fall tube goes down within the rising one, the mercury near the top of the latter is heated by the condensing mercury (thus economising gas and hence condensation does not take place until the vapour ha passed a considerable distance down the fall tube.-Prof. S. L Pickering read a paper on the theory of osmotic pressure and its bearing on the nature of solution. The author sard that considerable doubt exists as to the accuracy of the premise on which the theory is based, and if the theory is to be regarded as true and not merely a rough working hypothesis, the following conditions must be fulfilled by weak solutions-(1) The molecular depression of the freezing point must be independent of the nature of the dissolved substance. (2) Any deviations from (1) must be in the direction indicated by the theory. 3) the depression must be independent of the nature of solvent. (4) The depression must be independent of the amount al solvent (all solutions being weak). (5) The deviations with strong solutions should be in the theoretical direction, They should be regalar. Prof. Pickering proceeded to show that experiment, instead of confirming the above statements, disproves them all. As regards (1), without counting abnormally low (half) values, Raoult's results show variations of 60, 40, 30, &c., per cent. in different cases, and the author quoted values where the variations were 500, 260, 230, &c., per cent These variations, he considered, were too great to be explained by the fact of the solutions used being 3 or 4 times too strong. Referring to (2), he said that low values are reasonably ex plained by the polymerization of the dissolved molecules, lagh values by their dissociation into ions. He then argued that there are no abnormally high values, for the view that such exist, and that they are explainable by dissociation involves the following conclusions: (a) that the more stable a substance is the more easily is it dissociated; (6) that solution dissociate molecules which we know can exist undissociated as gases; that water must consist of 1H,O, and the atomic theory & wrong; (d) that energy can be created, and therefore the the ty of its conservation is untenable. With respect to (3), it wa pointed out that in many instances the same dissolved substance gives the full depression with one solvent and half depression with another. Cases were quoted where the depression pres duced by the same dissolved body in different solvents showe variations of 36,000, 21,000, and 28,000 per cent. In discussing (4), the author said that even with solutions weaker than the corresponding to a gas, the law is not fulfilled. Taking the case of sulphuric acid (the only one at present fully investgated), the variations amount to 40 per cent., or about 5 times the experimental error. With reference to (5), it was stated that with strong solutions the molecular depression should become smaller, but in every known case (9 were quotesit it becomes larger, the increase in one instance being 3,300 pr

her

cent. As regards (6), all experimental data available, especially these relating to sulphuric acid, show that the deviations are neither regular nor always in the same direction. Mr. T. H. Blakesley said he was greatly interested with Prof. Pickering's paper, for some time ago he was induced to make experiments n the volume of salts in solution by reading Joule's papers on that subject. Some of the results confirmed, but others did not agree with, Joule's theory that the molecular volume in soluion was a whole number. If this theory was true, then (he said) it would be possible to predetermine the density of solutions, and from the measured density of any known solution we could determine the water of crystallization of the salt from the

Chemical Society, March 6.-Dr. W. J. Russell, President in the chair. -The President announced that the senior Secretary would attend the meeting to be held in Berlin on March 11 to celebrate the 25th anniversary of the promulgation of Prof. Kekule's benzene theory, and would present a congratulatory address from the Society.-The following papers were read:-Some crystalline substances obtained from the fruits of various species of Curus, by Prof. W. A. Tilden, F. R.S., and Mr. C. R. Beck. The authors have examined the solid matters which are deposited from freshly extracted oils of limes, lemons, and bergamot made by hand. The substance, limettin, obtained from oil of limes (C. limetta) has the composition CHO, and crystallizes in tufts of needles melting at 121°-132°. It is neither an acid nor a glucoside, is not acted upon by acetic chloride or phenylhydrazine, and yields phloroglucol, and acetic nd formic acids on fusion with potash. Essence of lemons yields a substance, C1,H1O, very similar to limettin in appearance, though the crystals are more lustrous and melt at 116°. Bergamot yields a compound which crystallizes in colourless prisas and melts at 270°-271°.-Reduction of a diketones, by Prof. F. R. Japp, F. R.S., and Dr. F. Klingemann. Benzil, when reduced by boiling with fuming hydriodic acid for a few minutes, gives an excellent yield of deoxybenzoin. Phenanthraquinone, under like conditions, gives so-called phenanthrone, which, contrary to Lachowicz's view, is not the deoxybenzoin of phenanthraquinone, but a mono-hydroxyphenanthrene. -Studies on isomeric change, No. IV; halogen derivatives of quinone, by Mr. A. R. Ling. The experiments of Hantzsch and of Netzki have proved, in opposition to those of Levy, that the "anilic acids are paradihydroxy-derivatives of quinone, and Hantzsch and Schniter have shown that an isomeric change Occurs when paradichloroquinone is brominated, the product being metadichlorometadibromoquinone. The author has inestigated the action of bromine on paradichloroquinone and facetylparadichloroquinol, and the action of chlorine on paradibromoquinone, and has obtained results which confirm Hartzsch and Schniter's conclusion, since all attempts to CBr.CCI

prepare paradichloroparadibromoquinone, CO

CO

CCI.CBr

CO,

Jave been unsuccessful, the product in every case consisting of the isomeric metadichlorometadibromoquinone, CCL.C Br CCL.CBr arbamic acid, by Prof. A. E. Dixon.-Contributions to the chemistry of thiocarbamides; interaction of benzyl chloride and of allyl bromide with thiocarbamide, phenyl. and diphenylthiocarbamides, by Mr. E. A. Werner.

CO.-Note on a phenylic salt of phenylthio

Geological Society, March 12.-Mr. J. W. Hulke, F. R. S., Vice-President, in the chair.-The following communications were read-On a deep channel of drift in the valley of the Cam, Exsex, by W. Whitaker. In Scotland and in Northern Engand long and deep channels filled with drift have been noticed,

but not in Southern England. For some years one deep wellsection has been known which showed a most unexpected thickness of Glacial drift in the higher part of the valley of the Cam, where that drift occurs mostly on the higher grounds and is of no very great thickness. Lately, further evidence has come to hand, showing that the occurrence in question is not confined to one spot, but extends for some miles. The beds found are for the most part loamy or clayey. At the head of the valley various wells at Quendon and Rickling show irregularities in the thickness of the drift, the chalk coming to or near the surface in some places, whilst it is nearly 100 feet below it sometimes. Further north, at Newport, we have the greatest thickness of drift hitherto recorded in the South of England, and then without reaching the base. At one spot a well reached chalk at 75 feet; whilst about 150 feet off that rock crops out, showing a slope of the chalk surface of 1 in 2. In the most interesting of all the wells, after boring to the depth of 340 feet, the work was abandoned without reaching the chalk, the drift in this casereaching to a depth of about 140 feet below the level of the sex, though the place is far inland. The chalk crops out about 1000 feet eastward, and at but little lower level, so that there is the abrupt way in which drift comes on against chalk has been a fall of about 1 in 3 over a long distance. At and near Wenden seen in open sections. Two wells have shown a thickness of 210 and 296 feet of drift respectively; and as the chalk comes to the surface, at a level certainly not lower, only 140 yards from the latter, the chalk surface must have a slope of 1 in less than 1, and this surface must rise again on the other side, as the chalk again crops out. The drift here reaches to a depth of 60 or 70 feet below the sea level. At Littlebury, in the centre of the village, a boring 218 feet deep has not pierced through the drift, which reaches to 60 feet below the sea-level. As in a well only 60 yards west and slightly higher, the chalk was touched at 6 feet, there must here be a fall of the chalk surface of about 12 in 1. Eastward, too, on the other side of the valley, the chalk rises to the surface. The places that have been mentioned range over a distance of 6 miles. How much further the drift-channel may go is not known, neither can we say to what steepness the slope of the underground chalk surface may reach; the slopes given in each case are the lowest possible. The author thinks that the channel has been formed by erosion rather than by disturbance or dissolution of the chalk. After the reading of the paper there was a discussion, in which Dr. Evans, Mr. Clement Reid, Mr. Topley, Mr. J. Allen Brown, Dr. G. J. Hinde, and the author took part.-On_the Monian and basal Cambrian rocks of Shropshire, by Prof. J. F. Blake.-On a crocodilian jaw from the Oxford Clay of Peterborough, by R. Lydekker.-On two new species of Labyrinthodonts, by R. Lydekker.

Linnean Society, March 20.-Mr. W. Carruthers, F.R.S., President, in the chair.-After reading the minutes of the last meeting, the following resolution, moved from the chair, wasunanimously adopted :-" On the occasion of a gift, from Mr. Crisp, of a handsome oaken table for the meeting room, the Society desires to record its deep sense of the valuable services rendered by that gentleman, not only as Treasurer, but by numerous acts which are not generally appreciated because they are practically unknown to the Fellows."-Prof. P. Martin Duncan, F. R.S., exhibited several specimens of Desmophyllum cristagalli obtained from an electric cable at a depth of 550 fathoms. Though showing great variation in the shape and nature of the wall, the specific characters of the septa were maintained. The core, extending as a thin lamina far beyond the peduncle, had no connection with the septa. A section of Caryophyllia clavus showed theca between the septa, and a section of Lophohelia prolifera exhibited a true theca extending beyond the septa.-Mr. E. B. Poulton, F. R.S., exhibited some Lepidopterous larvæ showing the variation in colour induced by natural surroundings; and some lizards, in spirit, from the West Indies, showing the pineal eye very distinctly. In continuation of a former paper on the external morphology of the Lepidopterous pupa, Mr. Poulton gave a detailed and interesting account of the sexual differences observed in the development of the antenne and wings.-Prof. G. B. Howes read a paper on the intestinal canal of the Ichthyopsida, with especial reference to its arterial supply. He described certain arteries hitherto unrecorded, and some variations he had found in them in the Frog and Salamander. The artery known in the Elasmobranchii as the inferior mesenteric, was shown to belong to

the superior mesenteric series. Discussing the morphology of the intestine and its derivates, the author defined the large intestine of the Pisces more precisely than had hitherto been done, and showed that the appendix digitiformis of the Elasmobranchs must be regarded as homologous with the appendix vermiformis of mammals, and that a short cæcum coli is present at any rate in the Batoidei. The anatomical relationships of the appendix digitiformis were described in certain Elasmobranchs for the first time, and some notes were added upon the cæcum and large intestine among Teleosteans.-An interesting paper was then read by Mr. R. A. Grimshaw, on heredity and sex in the honey-bee.

PARIS.

Academy of Sciences, March 24.-M. Hermite in the chair.-M. Mascart presented a note on a direct-reading transmission dynamometer with a photographic registering arrangement, and also one on the Observatory at Tananarivo, setting forth some of the meteorological work to be undertaken in this new Observatory.-M. Berthelot, in a paper on the condensa tion of carbonic oxide, and on the penetrability of glass by water, says that he has been unable to obtain evidence of the transmission of water through glass under the influence of the silent discharge, and finds that the carbonic oxide is truly condensed into a body which rapidly takes up moisture from the air. Under agricultural chemistry, M. Th. Schlosing makes some remarks relative to the subject of M. Berthelot's observations on the reactions between soils and atmospheric ammonia, and discusses the differences of opinion existing between them. M. L. Ranvier, in microscopical observations of the contraction of living muscular fibres striated and unstriated, has contrived a method by which muscles may be excited whilst being viewed under a microscope, and from comparative observations of muscular elements in repose and contracted, finds that the homogeneous period and the inversion imagined by Merckel does not exist. On the regulation of the motion of governors by an auxiliary dynamɔ, by M. A. Ledieu. -On the Cretaceous Echinodermata of Mexico, by M. Cotteau. Descriptions are given of six specimens received from Mexico. The specimens are interesting both from a zoological and geological point of view, since they determine the age of the strata in which they were found.— In studies on the capture theory of periodic comets, M. O. Callandreau extends the elaborate work done by M. Tisserand on the same subject.-On the discovery of a remarkable transcendental function, by M. Fredholm.-On the invariants of a class of equations of the first order, by M. Z. Elliot.Relation between the volume, the pressure, and the temperature of different vapours, by M. Ch. Antoine.-Comparative study of specific inductive power, and of the conductibility of spaces filled with rarefied air, by M. James Moser. From the study of these properties with spaces containing air in three states of rarefaction-namely, (1) at a pressure of 10 mm. of mercury, (2) at I mm. pressure, (3) with an extreme vacuum-the author deduces that while the conductibility varies the specific inductive power remains constant. -Electrolysis of a mixture of two salts in aqueous solution, note by M. L. Boullevigne. Using a mixture of Zn and Cu salts, it is found that the conposition of the brass deposited varies rapidly with the intensity of the current employed, contrary to Buff's law. Considering the variation to be due to the chemical action of the sulphate of copper upon the zinc in the alloy deposited, and that the amount of this action is proportional to the time, an expression is found which allows the composition of the alloy obtained with any given intensity to be calculated with a fair degree of accuracy as tested by experimental results. A new method of preparation of betaines, by M. E. Duvillier. The author uses a reaction similar to that by means of which M. Schützenberger obtained the leucines synthetically; an ethereal iodide is caused to act upon the zinc salt of an amide acid in the presence of zinc oxide.-Titration of acetone by the iodoform reaction, by M. G. Arachequesne.-On callose, a new fundamental substance existing in cell membranes, by M. Louis Mangin. -The estimation of fatty matter in milk, by M. Lezé.

100 parts

of milk are heated in a flask with a graduated neck till the mixture becomes brown, ammonia is added till the whole becomes clear, the fatty matter rising to the top and its volume being read off on the graduated neck.-On new forms of crystallized silica, note by MM. Michel-Lévy and Munier-Chalmas.-The solubility of some substances in sea-water, by M. J. Thoulet.On the development of siliceous sponges and the conformation

of leaflets among the sponges, by M. Yves Delage.-On the physiological mechanism of hatching, sloughing, and mets morphosis among Orthopterous insects of the Acridean family, by M. J. Kunckel d'Herculais.-On the great sand dunes of de Sahara, note by M. G. Rolland.-On the gypseous formations of the Paris basin, and on the siliceous deposits which have replaced the gypsum, by M. Munier-Chalmas.-On the phy logical action of arsenietted hydrogen, by MM. F. Joly and £. de Nabias. On the diarrhoeic action of cholera cultures, by M. N. Gamaleia.-On the vibration of the earth at Chung-Hai and the movements of the compass at Zi-Ka-Wei during this vilta. tion, by M. Chevalier. It is remarked from observations tha the vibrations of the earth are unaccompanied by magnet disturbances.

BERLIN.

Physiological Society, March 14.-Prof. du Bois-Reyma President, in the chair.-Dr. Heymans spoke on myelin, giving a concise account of the numerous chemical and scanty micr

scopical investigations of what Virchow had designated as mivel i formations in peripheral nerves. From a chemical point of vi the controversy had turned chiefly upon the existence or un existence of Liebreich's protagon. The speaker had made n vestigations on frogs' nerves, from which he concluded that br protagon and lecithin are present in them, and that myelin formations are due to imbibition, with simultaneous producti of an external membrane.-Dr. Goldscheider gave an account of his researches on the sensitiveness of the articular surfaces if joints, based upon experiments on the tibial and metatarsal 1919 in rabbits. It appeared that the sensitiveness was dependent not so much upon the irritability of the surfaces of the joints, as of the of the epiphyses. The greatest effect was produced by direc stimulation of the marrow of the respective bones, while stimui tion of the compact bone-substance showed that this was quie insensitive.