Now there is I think preliminary evidence to show that both kinds of weather are due very greatly, if not altogether, to changes in the sun, a large declination-range, and a large temperaturerange denoting an increase of solar power. There is also evidence that temperature-range weather once produced travels from west to east, taking probably on an average eight or nine days to cross the Atlantic.

There is also, I think, preliminary evidence that declinationrange weather travels likewise from west to east, but quicker than temperature range weather, taking about two days to cross the Atlantic.

Now if this be true it might be expected that the declinationrange weather of to-day should be found similar to the temperature-range weather six or seven days afterwards, so that by a study of the declination-range weather of to-day, we should be able with a certain measure of success to predict the temperature-range weather six or seven days afterwards.

I have here given the train of thought which led to this investigation, but, I ought to say that the results obtained do not depend upon the exact truth of every step of this train of reasoning.

This is in reality a matter of fact investigation undertaken with the view of ascertaining whether or not there is any recognisable connexion between these two weathers in Great Britain. The result obtained I may add was reported to the Solar Physics Committee, and by them communicated to the Royal Society.

In order to avoid as much as possible the influence of locality, I obtained through the kindness of the Meteorological Council the diurnal temperature ranges at Stonyhurst, Kew, and Falmouth for the years 1871 and 1872. I obtained likewise through the kindness of the Kew Committee, the diurnal ranges of magnetic declination at the Kew Observatory for the same two years, excluding disturbed observations. The temperature ranges discussed are therefore the means of those at the three observatories above mentioned, and still further to tone down or equalize individual fluctuations, the daily numbers exhibited are each the sum of four daily ranges the two before and the two after. Finally the object being to represent fluctuations of range rather than their absolute values, a daily series representing the mean of twenty-five daily numbers has been obtained. Each daily number is thus compared with the mean of twenty-five daily numbers both columns being symmetrically placed with regard to time and the differences whether positive or negative between the two columns is taken to represent temperature-range fluctuations. A precisely similar course has been taken with respect to the Kew declination ranges.

By this means two years of daily numbers, sɔmetimes positive and sometimes negative, representing temperature range weather, and two years of daily numbers sometimes positive and sometimes negative representing declination range weather, have been obtained. The next object is to compare the two series

with one another.

Now when two series of waves representing elevations and depressions come together it is well known that we shall have the greatest result when the crests of the one series coincide with the crests of the other, and the smallest result, perhaps even none at all, when the crests of the one series coincide with the hollows of the other. This indeed is the well known explanation of musical beats.

Now if there be any marked likeness between the two weathers and if it be true that declination-range weather precedes temperature weather by six or seven days, the algebraic sum of the two sets of fluctuations representing these weathers will be greatest when the declination is pushed forward in point of time so that the declination fluctuations of to-day shall be summed up with the temperature fluctuation six or seven days after.

For suppose that the declination fluctuation of to-day is represented by a very large positive number; if the above theory be true, the temperature fluctuation six or seven days afterwards will be represented by a large positive number also, so that we shall have the addition of two large positive numbers, whereas, if we add the declination weather of to-day to the temperature weather of to-day it may chance that we are really adding a large positive to a large negative quantity in which case the result will be very small. It may also happen that this amount of precedence of declination-weather is greater at one season of the year than at

another.

We have therefore to pursue a plan somewhat of the following nature. Take a month's temperature-weather say for the month

of August and add to it a month's declination-weather, extending say from July 21st to August 21st, let the sum be 262. Here the declination month has been pushed forward II days. Next push it forward 12 days and let the sum be 273, then 13 days and let the sum be 276, next 14 days and let the sum be 270. It thus appears that the greatest sum is got by pushing the declination forward 13 days, and we may therefore presume that at this season of the year 13 days denotes the precedence of the declination weather.

On this principle the following table has been constructed. Table showing by how many days the declination-range fluctuation precedes the corresponding temperature-range fluctuation. Corresponding to middle

of month.

January
February

March
April

May

June

July August September October November December

Precedence of Declination. Second year.

First year.

8

Mean. 8

4

...

5

5

5'5

5

9

9

It thus appears from each year that the precedence of declination is smallest about the equinoxes, and greatest about the solstices, and it seems probable that were a considerable number of years so treated, more exact values would be obtained. Having thus determined the amount of precedence of the declination from month to month, the next point is to ascertain to what extent the two fluctuations when brought together in a manner regulated by this precedence show any distinct resemblance to each other. This has been done in a graphical representation which accompanies the report above-mentioned and I think I may say that there is a considerable likeness between the two curves, the one exhibiting temperature-range weather and the other declination-range weather so pushed forward.

It would thus seem as if a comparison of magnetical and meteorological weather might be made a promising subject of inquiry besides being one which may perhaps lead to results of practical importance.

On a Supposed Connection between the Heights of Rivers and the number of Sunspots on the Sun, by Prof. Balfour Stewart, M.A., LL.D., F.R.S.-While a connection between the state of the sun's surface as regards spots, and the magnetic state of the earth, may be considered as well established, the fact of a connection between sunspots and terrestrial meteorology is still sub judice, and without attempting to assert the truth of such a connection, the following may perhaps be regarded as a slight contribution tending to throw light upon the subject. The beights of the rivers Elbe and Seine have already been examined by Fritz, who reported in favour of such a connection as would make a great height correspond to a large number of sunspots, and all that I have done has been to treat the evidence in a somewhat different manner. I divide each sun period without regard to its exact length into twelve portions, and put together the recorded river heights, corresponding in time to similar portions of consecutive sun-periods. I find by this means residual differences from the average, representing the same law whether we take the whole, or either half of all the recorded observations, and whether we take the Elbe or the Seine. This law is that there is a maximum of river height about the time of maximum sun-pots, and another subsidiary maximum about the time of minimum sunspots. It is of interest to know whether the same behaviour is followed by the River Nile. Through the kindness of General Stone Pacha, and through the Science and Art Department, South Kensington, information has been obtained about this river. This informa. mation shows us that the Nile agrees with the European rivers in exhibiting a maximum about the times of maximum sunspots and a subsidiary maximum about the time of minimum sunspots, only the subsidiary maximum is greater than for the European rivers already named. It also appears that the date of maximum height of the Nile is latest on these years for which the yearly height is greatest. Now the present year is, perhaps, not very far removed from a solar maximum, and I am thus induced to think that the Nile may this year be somewhat late in attaining its maximum rise.

Contact Makers of Delicate Action, by Prof. H. S. Hele Shaw. -The author has been engaged in designing a speed indicator in which it is essential to have the uniform motion of a revolving disk. This disk is subject to varying resistance, so that for driving it, clockwork, even though powerful and expensive, could scarcely be depended upon. It therefore seemed best to employ an electro-magnet acting on a ratchet wheel and controlled by a clock. This clock for the purpose might then be a common one, with lever escapement. Upon enquiry there appeared to be no contact maker at once, absolutely reliable, suitable for continuous use, and at the same time sufficiently delicate in its action.

In an instrument of this kind for completing circuit it is necessary to ensure such a close approach of the surfaces forming the opposite poles as practically amounts to absolute contact. With small differences of potential and without previous contact, the exact distances across which the current will flow appears to be at present unknown. According to Prof. Guthrie the terminals of 50 or 60 grove cells may be brought to within 1-1000th of an inch without any indication of the passage of a current. Prof. Tyndall says that a battery of more than 1000 cells is required to cause a spark at 1-1000th of an inch, and Prof. Sylvanus

Thompson mentions 1-10,000th of an inch as the distance. To ascertain the quantity exactly, appears impossible without the use of an instrument of such refinement as Whitworth's millionth measuring machine, a modification of which might be very appropriately employed for the purpose. The distance no doubt is extremely small, and the consequent difficulty in the way of ensuring electrical contact when the opposite poles are the surfaces of two solids, seems to merit a brief consideration.

The ways in which two such surfaces are brought together may for convenience be divided into (1) a relative motion of the two terminal surfaces, normal to both; (2) a motion tangential to both; (3) a motion compounded of these two. The first mode is very common with rapid contact makers, such for instance of those with electric bells and telegraphic transmitters, but these require an appreciable amount of force to work them. That contact makers of this kind are not suitable with delicate clocks is the testimony of every clockmaker to whom the author has spoken One of these instruments of very delicate construction required the weight of nearly one gram to ensure electrical contact, and then could not be entirely relied upon. There is no doubt that when two surfaces of solids touch only lightly the area of contact is exceedingly small. This area may be made

to increase by increasing the pressure with which they are brought into contact. The conditions of the problem under consideration do not admit of this being done to any appreciable extent. Thus, even when chemical compounds are prevented from forming on the surfaces, dust and particles floating in the air are liable to become deposited between them, and render contact

uncertain.

For these reasons contact of the second kind which is known as rubbing or sliding contact has been largely adopted. This action may be made perfectly reliable, and is suitable where the motion is not rapid as for instance with switches and commutators. But considerable energy may be absorbed in overcoming friction. Those clockmakers who employ it, appear to do so only for large clocks. The third method has, as far as the author is aware, been adopted in only one way, though in that way with eminent success. A contact maker of this kind is used by Mr. Hargreaves of Leeds, who has had it at work for fifteen years. A metal roller with rounded edge runs upon and between two metal rails of circular section, thus making contact between them. Contact is broken when the roller passes over a gap or joint to another pair of rails. When the roller is moving along the rails, there is a slight rubbing action, by reason of its resting between them. This is almost certain to produce electrical

contact, which is even found to occur without failure when the whole is covered with dust. The metal employed is gold, which with a weak current, is found to last much better than even platinum. With a strong current the metal oxidises, and more over, though working admirably with a heavy pendulum, the resistance is too great for a delicate escapement to overcome.

The use of a liquid terminal with which the the other terminal (being solid) is brought into contact obviates most of the foregoing difficulties. Of all liquids mercury is the only one which can be practically employed. There are two objections to its use which have hitherto prevented its being used for more than temporary and experimental purposes:

I.

The fact that it readily combines with oxygen on the passage of an electric spark.

2. The difficulty of rendering a contact maker of this kind portable.

The author has endeavoured to overcome the first of these by causing contact to be made in a gas which has no action on the mercury. The way in which this is done is as follows: A short glass tube closed at its upper end (such as an inverted test tube) is filled with mercury, and inverted in a ves-el of mercury. The mercury is then partially displaced by hydrogen gas. A very light bent lever working on a pivot is connected with a platinum

W

wire, which passes through the mercury into the gaseous space. It there makes contact between the mercury below, and a smaller quantity in an insulated capsule within the tube. The lever is worked from the outside by mere contact with the escapement wheel of an ordinary clock, which owing to its extreme sensitiveness is quite sufficient to do this. The positive and negative poles of the terminals are connected respectively with the mercury in the capsule and that in the vessel. It is evident that although the lever is always in electrical contact with the mercury in the vessel, the circuit is only completed when it is brought into contact with that in the capsule.

Various experiments have been made with this instrument, and the result has been completely satisfactory. With a battery of fifteen Grove cells the surface of the mercury was brighter at the end of half an hour than at the beginning of the experiment, although a much more brilliant spark was visible than when eontact was made in air. After three weeks of intermittent working for periods of sometimes as much as twelve hours but with weaker batteries, the mercury remained quite clean.

The present form of the instrument is shown in the annexed figure. The general action is similar to the one already described A, being the gaseous space, D, the capsule of mercury, E, the escapement wheel. The chief improvements to be noted are:

1. Con'act is made and broken at F instead of at D, thus preventing sensible loss by volatilization from the small quantity of mercury in the capsule. The wire D F is insulated from the bent lever by the glass junction at H.

2. Portability is secured by having a plug, K, shown in dotted lines, which can be screwed down and a gland L, by means of which the wire can be packed by an india rubber washer, M. The lever and balance weights, w w, are made to go within the lid which can be taken off the bottom and screwed on to the top (as shown by the dotted lines). This keeps in any loose mercury above the plug.

3. The lever is so arranged that contact is only of momentary duration, a point of no little importance in connection with the constancy of the battery.

SECTION C-GEOLOGY

On the Geology of the Channel Tunnel, by Prof. W. Boyd Dawkins, F.R.S.-He laid special stress on the fact that the line of faults both on the English and French coast are small, neither of them have throws of more than 38 feet, and even this magnitude is rare, he therefore considers the chances of the older porous rocks being thrown by them is well nigh impossible. He considers, however, that in some cases this fault acts as ducts conveying water downwards, and he ascribes to one of these faults the well-known springs on Abbot's Cliff, known as the "Lydden Spout." 1. The lower beds of the chalk marl and the lower part of the grey chalk, are the only strata in the chalk sufficiently impervious to allow of the construction of a tunnel in the dry. 2. That the ou crop of the chalk marl between Folkestone and the Shakespeare Cliff, is the best position for a tunnel, which could strike the lower part of the chalk marl, and remain in it throughout, so as to join the workings of the French Channel Company, which are being carried on in the same horizon. 3. That the faults in the lower part of the chalk would not now allow of free percolation of water, and are not likely to become a serious obstacle to the work. 4. That the strata above the chalk marl are so porous and traversed by open fissures that they allow of free access to water both sub-aerial and marine. He c siders that on the French side the rocks are far more shattered and faulted, and more open to be traversed by water, which is now, however, being successfully contended with by the French Company. The author refers to analyses made of samples of cretaceous rocks. Insoluble material in gault was 45 per cent. ; chalk marl (No. 1), 75 per cent. ; and only per cent. in the more soluble part of the grey chalk; over the yellow chalk 18 per cent.; while above this it is only 2 per cent. in the lower white chalk without flints. He described the work done by Sir John Hawkshaw in having soundings taken in the English Channel to ascertain the character of the Channel bottom.

On the Proposed Channel Tunnel in its Geological Aspects, by C. E. De Rance, F.G.S., described the sub-divisions found in 1874 in the chalk of Abbott's Cliff, by Mr. Hilton Price and himself, and the impermeable nature of the lower beds, which support a sheet of water met with in springs at the outcrop, and in wells at various points. He regards these underground waters as circu

lating in the porous white chalk under the sea, and he considers that the artificial abstraction of water by pumping, in making the proposed tunnel in St. Margaret's Bay, will allow the percolation of sea-water to the extent of a million gallons of water in cach mile driven daily, and therefore offers great difficulties in the way of the construction of a sub-marine tunnel which are not presented by the lower beds of the chalk marl.

Evidence of Wave Action at a Depth of 40 Fathoms in the English Channel, by A. R. Hunt, B. A., describes 16 localities in which pebble have been dredged off the Start Point in 34 fathoms of water, and the discovery of a soda water bottle covered with Seri ulæ, and containing 36 species of shells which have been washed in, at a depth of 40 fathoms, by a Brixham trawling fishing boat.

List of Works on the Geology and Paleontology of Oxfordshire, Berkshire, and Buckinghamshire, by W. Whitaker, B. A.-This is a continuation of the County or District Lists, of which a cata. logue was given at the head of the Welsh List in the Report for 1880; the present list contains nearly 300 references.

On the Equivalents in England of the "Sables de Bracheux," and of the Southern Limits of the Thanet Sands, by J. Prestwich, M.A., F.R.S.-The author dwells on the importance of establishing in adjacent separate basins, a certain number of welldefined horizons. The lignitic and freshwater beds of the Paris Basin, and of the Woolwich and Reading series, form one such, but he considers the correlation of the beds beneath to be not yet satisfactorily established. The author correlates the Mancheux sands with the lower ends of the Woolwich series, and he is confirmed in this view by M. Desharges, and he further is of opinion that the Thames sands are absent in the Paris Basin.

On the Formation of Flints, by Prof. W. J. Sollas, M.A.Flints are siliceous pseudomorphs after chalk. Three different stages in their formation are to be distinguished: (1) the silicification of the foraminifera, coccoliths, and calcareous granules of the chalk gives rise to siliceous chalk; (2) a deposition of silica follows androduces white or grey flint; (3) as the deposition of silica continues it fills up and obliterates the pores of the opaque grey flint, rendering it black and translucent, thus the common black flint re ults. Flint nodules are sometimes found in which all three stages are still represented, but more frequently only the last two: thus grey spots and blotches are seldom absent from black flint, whilst in many cases the two kinds regularly alternate and thus produce the phenomenon of banded flint, which has up to this time remained without any satisfactory explanation.

On some Fossils from the Inferior Oolite, by the Rev. G. F. Whidborne, M.A., and Prof. W. J. Sollas, M.A.-Describes bivalve shells of mollusca chiefly in the Jermyn Street Museum, and 8 new species of sponges, of which 4 belong to 4 new genera.

Mention of an Example of an Early Stage of Metamorphic Changes in an Old Red Sandstone Conglomerate near Aberfoil, by Prof. James Thomson, LL.D., F.K.S., describes fractured quartzite pebbles which he regards as originally a plastic body, which first bent, and then broke, and that the present brittle appearance has been induced at a late era, and he refers their origin to metamorphic action.

On Features in the Glacial Workings noticed on Sandstone Conglomerate at Skelmorlie and Aberfoil, by Prof. James Thomson, LL.D., F.R.S., describes a railway cutting half a mile from Aberfoil. At 150 to 200 feet above the sea occurs striated sandstone, on which were glaciated pebbles, behind which occurred tails of fine material, 5 or 6 feet in length, in the direction in which the ice travelled. Examples have been found by the author showing distinct traces of the ice moving up hill.

Problems in the Geology of the Channel Islands, by the Rev. E. Hill, M. A., states the work done by the late Prof. Ansted leaves much to complete, and is of opinion that there is here a fine field for detailed investigation.

Notes on the Geology and Mining of the United States of Columbia, S.A., by R. B. White.-This paper gives an exhaustive report of the range of metals in time and space in this region, and the application of facts ob-erved, to other districts.

Suggestion for a Revised Classification of the British Eocene, by J. S. Gardner.-Some modification in the classification of the Eocene has become desirable, through the transfer of the Upper Eocene group of Edward Forbes to the Oligocene formation. The discovery of several distinct floras seems also to necessitate certain alterations in order to bring periods founded originally

on changes in mollusca into harmony with the more striking changes indicated by the plants. A grouping is suggested which separates the London Clay from the Lower Eocene, and brackets it with the Lower Bagshot Beds as a Middle Eocene. The Middle Bagshot series forms the Upper Eocene, while the Upper Bagshot may remain a member of the same formation, or find a place in the Lower Oligocene. Refers to the changes of climate in the Tertiary epoch.

On the Classification of the Oligocene Strata in the Hampshire Basin, by J. W. Elwes, describes results of investigations in Hampshire and the Isle of Wight. In the latter district he considers that Prof. Edward Forbes was correct in stating that there is only one marine series in the Headon and Brockenhurst group, but he considers, with Prof. Judd, that there are at least two marine zones, the Brockenhurst zone, lying at the base of the series, instead of above the Middle Headon Venus bed. The author found the southerly dip at Totland Bay, as described by Prof. Judd, bnt found no evidence of the local flexure described by that author, by which the latter explains this section, in opposition to the view of the late Edward Forbes.

On the Outcrop of the Brockenhurst Beds near Lyndhurst, by E. Tawney, M. A.-Fossils characteristic of the rich beds which he had been lately working in the railway cutting near Brockenhurst, were found by Mr. H. Keeping, at Cut Walk Hill, Lyndhurst, in 1858. The well at Emery Down, closely adjacent also, yielded the same fossils in 1863. The excavations which the author had lately carried out with the assistance of the Rev. J. Compton, of Minstead, on several sides of this hill, show the succession of the beds to be on the base of the hill. Upper Bagshot sands, next in ascending order, freshwater Lower Heaton, Marine Brockenhurst bed, Voluta geminata zone, followed by beds not explored, concluding with the freshwater Osborne marls on the top of the bill. The succession is therefore that of Whitecliff Bay. The thickness of beds between the freshwater Lower Heaton and the Osborne marls is about 100 feet. The discovery of freshwater Upper Heaton beds at Roydon brick-yard was announced.

SECTION D-BIOLOGY

Department of Zoology and Botany

On a New Principle affecting the Systematic Distribution of the Family of the Torpedinida; and on the Probable Occurrence of the T. Occidentalis (Storer) on the British Coast, by Prof. Du Bois Reymond, F.R.S.-The author referred to the researches of Prof. Babuchin, of Moscow, on the development of the electrical organs of Torpedo, who has established that these organs are formed by the metamorphosis of striated muscle, and that as they grow they increase in size, not by the addition of new columns and septa, but by the growth of the columns and septa, so that the number is the same in adult and young specimens. He then passed on to the consideration of the part which this fact-known as "delle Chian's and Babuchin's Law-plays in the distribution of the Torpedinidæ. He thought that the average number of columns ought henceforward to form a part of the diagnosis of the species of Torpedinidæ a matter which has hitherto been entirely overlooked by zoologists. He referred to the species of Torpedo of John Hunter, and showed how Hunter's conclusion that the columns increase in number as well as size was erroneous, and described fully the T. occidentalis on the British coasts.

It

On Cephaliscus, a New Form allied to Rhabdopleura (Allman), by Prof. McIntosh, F.R.S.-This new form was very fully described, and its relation to Rhabdopleura of Allman, which we know as a somewhat abnormal Polyzoön, was discussed. differs from Rhabdopleura in regard to the canæcium, in the much greater size of the buccal shield, in the remarkable branchial or textacular plumes, in the structure of the pedicle, and the perfectly free condition of the polypides. Cephaliscus and Rhabdopleura agree in the absence of the calyciform membranes connecting the bases of the tentacles, in the position of the mouth, which opens behind the buccal shield, in the general structure of the alimentary canal, and in the position of the anus. The development of the young buds is similar. Both forms connect the ordinary Polyzoa with Phoronis.

On an Instructional System of Arrangement in Provincial Museums, by F. T. Mott.-The author suggests a combination of a typical collection of the entire fauna of the globe with that of the local species, the latter being on the ground row, both

scientific and vernacular names being given on labels corresponding with a cheap popular guide-book.

Injurious Parasites of Egypt, by Dr. Cobbold, F.R.S.Egypt is a grand field for the helminthologist, since not only is that country the headquarters, so to say, of one of the most dangerous of human parasites, but it swarms with others possess ing scarcely less practical importance, whilst it likewise enjoys the distinction of having made us acquainted with parasitic rarities not known to occur in any other part of the world.

The most dangerous parasite is Bilharzia hæmatobia. This was so named by me in honour of Dr. Bilharz, who first discovered it at Cairo in 1851. A few years later I detected the same species of parasite in a monkey; and since the year 1856 confirmatory discoveries and observations, made both at home and abroad, have very greatly extended, though they have by no means completed, our necessary knowledge of the natural history of the creature. In this connection it is fitting that we should signalise the labours of Dr. Prospero Sonsino, whose residence in Egypt has enabled him to contribute facts of great interest. It is to Sonsino that we owe our knowledge of the fact that cattle and sheep are also liable to be infested by Bilharzia, but the species is not the same as that which invades man and monkeys.

The Bilharzia is a genuine fluke parasite of the digenetic kind, and therefore requiring a change of hosts. It differs from the ordinary sheep-fluke and its allies in being unisexual. In other words we have male and female Bilharzia, the male being the stouter of the two sexes. This is an unusual circumstance amongst parasites. Again, these Bilharzia differ in respect of habitat, for, instead of occupying the liver-ducts and intestinal tract, as most flukes do, they take up their abode within the blood vessels of the victim.

Although the parasites are individually small, the slender females being less than an inch in length, the presence of any considerable number of them gives rise to a formidable malady, which, in some cases, proves fatal. The disorder thus occasioned has received various names, but it is sufficient to speak of it as the endemic hæmaturia of warm climates. Dismissing the purely professional aspect of the affection, and viewing the matter as a question of public health specially affecting European residents in Egypt, I may state that I have recently seen six officers of the Ea tern Telegraphic Company, who contracted the disorder in the neighbourhood of Suez, and also another gentleman who obtained the parasite in Natal. In all of these instances the immediate cause of the parasitic invasion was due to their having carelessly drank unfiltered water. In all the Egyptian cases this took place during shooting expeditions along the banks of the Cairo-Suez Canal.

Thus, all the evidence of a practical sort that we have obtained as to the cause of the endemic is in perfect harmony with that which has been derived from scientific inquiry. So far as our investigations have been pushed, it is clear that in respect of Bilharzia hamatobia, the natural history phenomena do not differ in any very essential particular from those that occur the case of ordinary flukes. We have a similar mode of origination, the same rapid growth and development attended with metamorphosis, and likewise a change of hosts.

Practically it is of little moment what water snail or other aquatic organism holds the cercaria of Bilharzia. Infection follows as well from the ingestion of the free-swimming cercaria as from the ingestion of the intermediate hosts. It comes to the same thing in the end. Canal water-drinking in Egypt is the direct cause of the Bilharzia infection, and of the consequent endemic hæmaturia. This being so, simple filtration is in most cases a sufficient protection. To European residents, therefore, the drying up or damming up of the fresh-water canals is not an unmixed evil, because it insures greater freedom from parasitic dangers; moreover, it induces efforts to remedy the evil. Of course these efforts will correspond in magnitude with the neces sities of the case.

Unfortunately, there are other parasites whose entrance into the human body by means of water-drinking is of constant occurrence, and they are often found associated together in one and the same per-on. The other specially obnoxious endemic worms are Anchylostoma duodenale and Filaria sanguinis hominis. Speaking of the collective role of the three parasites, Dr. Sonsino says that "they concur in the production of a large mor tality of the natives," and the mischief they thus occasion "is not sufficiently appreciated."

How fatal the Anchylostoma may prove in other countries

than Egypt was recently seen in the endemic outbreak which carried off some of the labourers during the formation of the St. Gothard Tunnel. Many disputes and misunderstandings at first prevailed respecting the role of this Entozoon. Having been called "tunnel trichinosis," this disorder got sadly mixed up with affections having a totally different character and history. Similarly, the blood-letting habits of Bilharzia and Anchylostoma having produced analogous symptoms, the two disorders were called Egyptian chlorosis, intertropical anæmia, and so forth. Recently our knowledge of the geographical distribution of the Anchylostoma has been extended by the discovery of Prof. McConnell, who finds that the parasite is more or less prevalent in India, Wherever it is to be found, its power for mischief is the same, and its mode of entrance into the human frame can only occur through the medium of water.

One

As regards dangers arising from external attacks by water parasites, little need be said. Troops invading foreign lands are now better furnished than formerly in the matter of clothing and other protective aids; still there are points worth mentioning, especially as in the heat of a campaign the distress from thirst often compels the soldier to drink the filthiest of waters. quotation will suffice During the invasion of Egypt by Napoleon, the French soldiers were much distressed, and often laid themselves flat on the ground to drink. Their mouths and nostrils were thus attacked by leeches. The species responsible for these assaults is the Hæmopis sanguisorba of Savigny. These free parasites not only attacked the men, but also their horses, camels, and cattle.

On the Brown Coloration of the Southampton Water, by Arthur Angell, Ph. D.--The author has found that this coloration is very irregular, and even occurs in isolated patches; he showed that the coloration is due to a brown organism (Pendinium fuscum); he has been able to obtain from it brown and green solutions, which both give the spectroscopic appearances characteristic of chlorophyll. He discussed its probable animal or vegetable nature, but favoured the latter view.

Department of Anatomy and Physiology.

Dr. Fraser proceeded to the description of his results on the early development of certain rodents, illustrating his remark by drawing on the board. He showed that the guinea-pig, instead of standing isolated among mammalia by its peculiar form of development, shared this isolation among rodents with the rat and the mouse. He traced the history of the ovum from the sixth day after union of the sexes, up to the formation of the allantoic circulation. Dr. Fraser, whose work is still incomplete, but who is at present busy with the earliest condition of the ovum, offered no explanation of this important result. He insisted, however, upon the hypoblastic layer being external from the close of segmentation, and that the inversion of the layer therefore existed in these three animals from the earliest segmentation phenomena.

Prof. Allen Thompson made some remarks upon the general excellency and result of the work as changing our ideas on the mammalian development, and stated that as Kölliker had just found the hypoblastic layer in the amnion of the rabbit, we must be prepared for great changes in our received opinion on this subject.

On the Homologies of the long Flexor Muscles of the Feet of Mammalia, by G. E. Dobson, M.A., M.B..-Dr. Dobson dealt with the homologies of the following muscles:-Flexor Digitorum fibularis = Flexor hallucis longus; 2. Flexor Digitorum tibialis Flexor Digitorum longus; 3. Tibitalis positicus. He explained by means of drawings how these muscles partially or totally supplanted one another in different animals. From the examination of a large number of animals he found the flexor fibularis existing in all and exhibiting but few modifications, while the other two were subject to much variation, or might be absent. He deduced from his dissections that the variation of the flexor tibialis had not been properly understood, its real homologues having been named tibialis porticus accessorius secundus, or internus, while it was supposed the muscle had undergone fusion with the flexor fibularis.

On the Nature of the "Telson" and "Caudal fusca of the Crustacea," by M. M. Hartog, M. A., D.Sc.-Dr. Hartog sent a short paper to explain that the telson in the higher crustacea is equivalent to the last segment of the Nauplius body, together with an immensely developed postanal portion composed in varying proportions of the supra-anal plate and the adnate fuscal processes. The fuscal processes he regards as outgrowths of this telson not

strictly comparable to limbs, but rather to the primitive-paired outgrowths of the body-segments which have become limbs elsewhere by the development of basal articulations and a proper musculature.

Considerations arising from Koch's Discovery of the Bacillus of Tuberculosis, by F. J. Faraday, F.L.S.-Two great discoveries, Pisteur's discovery of the decreasing virulence of specific disease germs when kept in the presence of oxygen, and Koch's discovery of the bacillus of tuberculosis, have been made within the past two years. The author suggests a possibly useful relation between these discoveries. Referring to the sugges tion of Dr. William Roberts, F.R.S., of Manchester, in hls address to the Medical Association in 1877, that disease germs may be "sports" from harmless saprophytes which have acquired a parasitic habit, he asks whether deprivation of oxygen, or cultivation in gaseous mixtures from which the normal supply of free oxygen present in good air is absent, may not have an influence in converting harmless germs present in the atmosphere into the bacilli of tuberculosis. He refers to Carl Semper's researches on the influence of the environment on animal modification, and to the fact that many larvæ of insects live in situations where the air is undoubtedly mixed with gases which the higher vertebrata could not breathe without injury, and suggests that the adaptability of organisms, and their im pressionability by surrounding conditions, may increase as the scale of life is descended. He also refers to a paper by Mr. Frank Hilton, F.C.S., read before the Chemical Society, on experiments with bacteria in various gases. Mr. Halton gave the chemical results, but it would be interesting to know the influence of cultivation in such media on the character of the bacteria themselves. Dr. Angus Smith has argued that the putrefying process, when carried on in confined places, such as sewers, may develop disease germs which are not developed when the same process goes on in unconfined places; typhoid fever seems to be developed by processes in sewers, which, carried on in the Clyde, for instance, do not originate any wellmarked disease. Analogous conditions may be presented in the lungs of persons engaged in dusty trades, breathing vitiated atmosphere in ill-ventilated rooms, or engaged in sedentary occupations, and not taking healthy exercise; and also in the lungs of persons who are hereditarily narrow-chested, weakly, and of feeble inspiratory habit. Innoxious germs present in the atmosphere may be inhaled and retained in the lungs of sush persons, and there by successive culture and deficient aëration acquire a parasitic or deadly character. The author refers to Pasteur's method of restoring the virulence of "attenuated " germs by successive culture in the bodies of different animals, as possibly explaining the communication of tuberculosis to persons of sound constitution, the parasitic habit of the tubercle "sport being so strengthened and confirmed by successive culture under the assumed favourable conditions as to enable it eventually to establish itself under certain conditions in a milieu which would not be suitable for the origination of the culture. He refers to a new treatise by Dr. Ferdinand Kroczak, of Brünn, entitled "Die Heilung der Tuberculose," and shows that Dr. Kroczak's arguments in support of the special treatment recommended by him are in harmony with the hypothesis advanced.

The decrease of mortality from consumption in the army since the improvement of barrack ventilation, and the relief afforded to patients by sea-voyages, the air of pine-woods, carbolic acid inhalations, and other suggested remedies, is also referred to as giving support to the hypothesis.

In fol

On the Kidneys of Teleostei, by W. Newton Parker. lowing the investigations of Prof. Balfour, who showed that in certain adult Teleostei, as well as in Lepidosteus and Accipenser, the so-called "head kidney" contained no urniferous tubules, but was composed entirely of highly vascular lymphatic tissue, the author finds that in some Teleostei the so-called "headkidney" has precisely the same structure as the rest of the kidney in mesonephros. He nevertheless holds that Prof. Balfour's view is correct, and explains the circumstance by supposing that the mesonephros has grown forwards so as to take the place of the larval pronephros.

On the Perception of Colour in Man and Animals, by Dr. S. D. Macdonald, R.N.-Dr. Macdonald read a paper, in which he endeavoured to show the near relationship of perception of sound and light, comparing different colours to different notes.

On the Structure of the Muscular Tissue of the Leech, by T. W. Shore. The author described his research, summing up as follows:-1. The muscle of leech consist of elongated tubes