merable and incalculable. For ventilation, aerating water without carbonic acid, for increasing the heat of blast-furnaces and the light of lamps, its uses are self-evident. The nitrogen, which was at first looked upon as wasted, has, by a process due to the same inventors, been turned into ammoniacal salts for manure. Most of the uses of these products were known. What is claimed is the almost fabulous reduction in the cost of production. The chemical textbooks, according to Messrs. Brin, are at fault as to the possibilities of baryta. They all teach that it is destructible; and the Brins maintain, that, as they know how to treat it, it is indestructible. Oxygen in large quantities means a revolution in half the processes of chemical industries.

Before the Amherst-college science association (see Science, v. iii. p. 340), the following addresses have been given, and papers read, during the past year: German university life, by G. G. Pond, M.A.; Origin of the vertebrate type, by Prof. J. M. Tyler; The chemistry of photography, by H. B. Ames; Artificial diamonds, by E. H. Smith; Chemistry and its relations, by Prof. E. P. Harris; Post-routes during the siege of Paris, by W. I. Fletcher, M. A.; Atomic weights, by W. H. Hallock; Relation of literature to science, by President J. H. Seelye; Torpedoes, by J. W. Morris; Relation of the mind to the body, by I. H. Upton; Storms, by A. F. Stone; Geology of regions about the Rhine, by Prof. B. K. Emerson; Marriage, by Dr. E. Hitchcock; Labrador, by W. A. Stearns; Astronomical photography, by Prof. David P. Todd; Nebular hypothesis, by Prof. B. K. Emerson; Migration of birds, by F. T. Jencks; Relations of animal to human psychology, by Prof. J. M. Tyler; Geology of South Africa, by B. N. Bridgman; How to choose a physician, by Dr. H. H. Seelye.

The geological survey of Pennsylvania has now collected the various maps of the Panther-Creek and other coal-basins of that state, to form part i. of its 'grand atlas' of the anthracite coal-fields. It contains twenty-six sheets relating to the eastern end of the western, middle, and southern fields in four counties of the eastern part of the state. They have been published before by instalments, and noticed by us at different times; but their collection into a single atlas marks a welcome stage of that part of the work, under the superintendence of Mr. Ashburner.

- Rear-admiral English, who was recently in the Kongo country, has made a report to the Navy department in regard to the advisability of establishing a commercial station at the mouth of the Kongo River, or of securing a limited district for a depot and

factorial establishment' for American citizens in that region. He says that the investigations made by Commander Bridgman and U. S. commercial agent Tisdell show that all the available land has been acquired for the nation by the trading-house employees, and is held at extravagant prices. Under these circumstances, Admiral English deemed it unnecessary to take any further action, and was of opinion that to establish a proposed coaling-depot at

the Kongo would be unwise and unnecessary. Admiral English quotes from a letter from Tisdell, in which he says, "The reputed wealth of the Kongo valley has been greatly exaggerated, and it will be an undesirable and unprofitable country for an American to make his home or to embark in any business enterprise. Between Vivi and Stanley Pool I saw on all sides misery, want, sickness, and death, particularly among the employees of the International association. The country does not and can not produce food for the white man to live upon, and barely produces enough for the natives." This opinion is confirmed by Commander Bridgman of the Kearsarge, who says that it would be unwise for the government to do any thing to encourage Americans to go to that region. Commander Bridgman has no faith in the future of the Kongo predicted for it by interested parties.

-At the meeting of the Gas institute held in Manchester, Eng., in June, Mr. William Gadd read a paper on the effects of heating air upon combustion. For a considerable period, on purely theoretical grounds, Mr. Gadd had strongly doubted the value of heated air at ordinary pressure as a means of intensifying or causing more perfect combustion. Recent investigations strengthened his doubts to an enormous extent. An observation made by Professor Dixon, in connection with some experiments on a certain regenerator-burner, in which he found that a small quantity of air let in at the bottom or lower part of the lamp much increased the intensity, produced a strong impression on his mind, and confirmed the views he had formed. He therefore resolved to devise some simple experiment which would determine the point. He employed many methods which showed, all of them, in some degree the expected result, and strengthened the belief in the discovery which theory pointed out. He was at last enabled to formulate a method to make the conclusions unmistakable and plain. He found a peculiar phenomenon of flame, which he termed a balanced flame of imperfect combustion.' In this he recognized the means for what he conceived to be complete demonstration of that which he had long suspected; namely, that, so far from the heating of air in passages at constant or ordinary pressure increasing combustion, it actually retarded or rendered combustion more imperfect. Mr. Gadd described his experiment, and produced before the meeting the balanced flame' he spoke of. His conclusions were strongly contested by several speakers.

FRIDAY, AUGUST 7, 1885.

THE INTERNATIONAL SANITARY CONFERENCE AT ROME.

EPIDEMICS are not an unmixed evil. Indeed, it would perhaps not be going too far to say, that, on the whole, they are productive of more good than harm. They call attention to sanitary sins, and lead to sanitary reforms, which, in the absence of such a special stimulus, would often not be made. As a result of these reforms, the mortality from endemic diseases is, no doubt, often reduced to an extent which would quickly leave a balance on the credit side if a careful life-account were kept with cholera or yellow-fever in areas outside of their endemic prevalence. Thus, for example, the epidemic of cholera in Naples last year has been the cause of a general sanitary awakening in that city, which has long been noted as a hot-bed of typhoid-fever and other preventable filth-diseases. It has led to the speedy completion of the new water-works, by which the city secures an ample supply of pure water; and the municipal authorities are now earnestly inquiring as to the best system of sewerage, with a view to introducing it as soon as possible. By the way, the writer suggested to the syndic (mayor), that the separate system' of Col. Waring would be best adapted to the special conditions found at Naples; and this suggestion received the indorsement of the famous Dr. Koch, delegate from Germany to the International sanitary conference.

One of the most prominent indications of the general agitation of measures relating to sanitary reform, which in civilized countries follows an epidemic, is the disposition on the part of a country which has been recently punished, to call upon its neighbors to make common cause with it against the deadly pestilence. Thus the International sanitary con

No. 131.1885.

ference of Constantinople (1866), that of Vienna (1874), and that recently called by the Italian government, which met in Rome on the 20th of May of the present year, have all been the direct result of a recent epidemic of cholera; while the incentive which caused our own government to invite other nations to send delegates to the International sanitary conference held in Washington in 1881, was the epidemic of yellow-fever which devastated the Mississippi valley in 1878, and re-appeared in Memphis in 1879. The object in view on the part of the various governments which have taken the initiative in calling together sanitary experts for an international conference, has been to establish by treaty an international and uniform code of sanitary regulations. Unfortunately this object has not yet been attained. Whether the conference of Rome will be more fortunate in this respect than its predecessors have been, remains to be seen; as it has not yet finally adjourned, but is to meet again in the autumn. In the mean time, the delegates are to confer with their respective governments, and to present for their consideration the conclusions reached by a sub-commission composed of the technical delegates, which must serve as the basis of an international convention, if one is finally arranged. Even if this desirable result is not attained, the conference, like those which have preceded it, will be productive of great good, especially in the country where it was held. The interchange of opinions among leading sanitarians from various countries, the formulating of the knowledge which has been gained in the laboratory, or by the practical management of epidemics, the publication of explicit directions relating to quarantine, disinfection, municipal and maritime sanitary supervision, etc., cannot fail to be useful. And, even if no novel preventive measures have been brought forward, the reiteration, with the authority of such an assemblage of experts, of well-recognized san

itary axioms, is of the greatest importance. For it is only under the stimulus of a recent epidemic, or the fear of one in the near future, that those who devote their lives to sanitary science can secure the attention of legislators, and of the public generally, to the truth of these axioms, and to the fact that cholera and yellow-fever are, to a great extent, preventable diseases.

Upon two things the sanitarians assembled at Rome, with two or three exceptions, were agreed: First, that cholera invades countries at a distance from that part of India where it exists as an endemic disease, not by de novo development, nor by any independent power of extension, but as a result of human intercourse. In other words, that new centres of infection are established by the transportation of germs from previously infected localities, either by fomites, or by means of the dejections of the sick. Second, that certain insanitary local conditions are essential for the development of an epidemic when cholera-germs are introduced; and that in a city which has a pure water-supply, and which is in a perfect sanitary condition, cholera cannot establish itself. So thoroughly are the English delegates to the sanitary conference convinced of the truth of this latter proposition, and so well are they satisfied with the present sanitary condition of their country, that they are willing to trust entirely to local sanitation, disinfection, and isolation of the sick, and insist that quarantine restrictions of any kind are unnecessary. In proof of this they point to the fact, that, for years, there has been unrestricted communication between the cholera-districts of India and England; and that, nevertheless, the disease has not been introduced into the latter country.

Other countries of Europe, however, are not willing to trust alone to local sanitation. They say, We admit that with plenty of money, a city may in time be made cholera-proof, especially if its inhabitants have been educated in ways of cleanliness, and if it is not located too near the tropics. But the cities and towns of southern Europe are not in this condition,

and it is hopeless to think of effecting such radical sanitary reforms on short notice. We therefore demand the establishment of barriers for the arrest of the infectious principle, or germ, which comes to us from your Indian possessions, and most frequently by way of the Red Sea and Suez Canal. In addition to this, we propose to guard our ports of entry, and to depend rather upon the exclusion of cholera-germs than upon the hopeless task of effecting such sanitary reforms as will make it safe to open the doors for their unrestricted introduction.

England replies, through her delegates to the conference at Rome, Guard your ports as closely as you please, but leave us free to pursue such methods as we have heretofore found efficient; and don't interfere with our commerce by detaining ships which are sailing directly from India to English ports by way of the Suez Canal.

As to the quarantine restrictions necessary, there is the widest range of opinion among the delegates to the conference at Rome. Some insist upon the old-fashioned arbitrary quarantine of detention for all ships and persons coming from infected ports, and differ only as to the time of detention. For these, from seven to ten days after arrival is the shortest time which can with safety be admitted. In this old quarantine party are the delegates from Turkey, Spain, Brazil, Greece, Roumania, and one or two other second or third rate powers. On the other hand, the delegates from France, Germany, Italy, Austria, Russia, the United States, and several other nations, advocated a more flexible system, which should take into account the sanitary condition of the vessel, the time she has been at sea since leaving an infected port, or since the last case of cholera occurred on board, etc. This system, commonly spoken of as the system of medical inspection,' includes the isolation of the sick; disinfection of soiled clothing, excreta, and of localities exposed to infection, including ships; and detention of the well for observation for a limited period-three to five days-if they have been recently exposed to infection.

native element to discover that the great dorsal and anal fins are almost its sole organs of propulsion. In the figure, both are shown with their tips thrown over to the right side. This movement is synchronous in these great fins; that is, both strike in the same direction at the same time. But the most remarkable feature about them is, that they are twisted into the form of the blade of a propeller-wheel at the commencement of each stroke, as shown (not very clearly) in the figure, where the foreshortened dorsal is indicated in the condition which it presents at the moment

MOLA ROTUNDA (viewed from above, y nat. size).

when the stroke to the left is about to begin. The direction of the peculiar twist of these fins is also reversed at each successive stroke, in opposite directions, so that a most effective propelling apparatus exists, which it would be somewhat difficult to imitate by a mechanical device. This contrivance is rendered all the more effective in consequence also of the great width of the fish, by which great stability is secured.

A very peculiar soft oval ring of dermal tissue around the bases of the dorsal and anal, renders them readily movable by means of the tendinous

terminations of the muscles which are inserted into the strong bases of their rays. A similar band of soft dermal tissue is found on both sides of the base of the broad, crenulated, rigid tail, which is moved on its base just as the rigid rudder-blade of a vessel is moved by means of the rudder-chains. In the case of Mola, however, the single pair of rudder-chains as found in a vessel is replaced by a single series of tendons on either side of the median line, running parallel, and passing through round canals in the soft elastic base of the caudal, and inserted into the bases of the caudal rays.

The office of the curiously modified caudal of Mola seems to be solely that of a rudder, no vibration whatever of the tail being apparent when the animal is swimming in a straight line. Only when the creature wishes to turn is it deflected from the median line at its tip; and even then its apex sweeps through an arc of not more than twenty-five degrees at most, usually much less.

The pectorals are comparatively small, and, in swimming in a straight line, are extended horizontally and kept rigid and motionless by the animal, as if merely for the purpose of keeping the body vertical. When swimming with the sides of the body at an angle with the plane of the horizon, one or the other of the pectorals is folded closely against the side.

It thus becomes evident that Mola uses almost exclusively the dorsal and anal fins as locomotive appendages, and that the tail and pectorals act respectively as the rudder and as balancers, and take no active, but only a very subordinate, share in effecting the creature's movements. Even the rudder-like tail may be said to be defective; for it was noticed that the fish, when first placed in the pool, was unable to turn quickly enough to avoid bumping its snout against the stone walls at the angles of the enclosure.

The organization of this creature is probably the most remarkable of any encountered amongst the Teleostei. The body is incased in a very thick inflexible skin, and all of the lateral musculature has become subordinated to the office of flexing the vertical fins. In fact, so extreme has been the muscular specialization, that the myotomes have been entirely suppressed, and the lateral muscular masses developed into long muscles, ending in tendons.

No less remarkable has been the mode in which the tail has been developed through a larval form, probably provided with a lophocercal tail, which has already disappeared in the stage represented by Molacanthus. Mola, in fact, is the best-known example of a type having a gephyrocercal structure. No less extreme is the modification of the cerebro-spinal nervous system; for, as a result of the muscular specialization already noticed, the medulla spinalis has been excessively abbreviated. We are, accordingly, forced to admit, that Mola is the most extremely modified teleost in existence, notwithstanding the fact that a great many very singular deep-sea forms have been described within a very recent period.

The great advantage of having the large pools of salt-water enclosed by heavy stone walls also becomes very apparent in the instance of Mola, and shows how valuable they may become as aids in the study of the habits and modes of life of such large marine forms as dolphins, porpoises, sharks, swordfish, etc., -types in which the Fish commission is interested, as affecting the abundance of certain of the foodfishes.

JOHN A. RYDER.