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gives the details of fourteen stars which have recently been found to have variable radial velocities, from plates taken by the D. O. Mills expedition to the southern hemisphere. The same author deduces the orbit of the spectroscopic binary v Centauri, giving the period as 137-939 days. This star is one of a group of Class B binaries, which have periods of about 130 days. Mr. R. F. Sanford describes his investigation of the orbit of the spectroscopic binary e Volantis, a star of magnitude 45 and of Class B5. The new elements show a period of 14-16833 days. A note by the same author on two spectrograms of the interesting irregular variable Carinæ indicates that the observations of 1913 and 1914 show no evidence of variation in radial velocity.
SOLAR RADIATION MEASURES IN EGYPT.-Bulletin No. 14 of the Helwân Observatory contains an account of some observations of solar radiation which have been carried out at the Helwân Observatory by Mr. Eckersley. It has been shown by Prof. Abbot that values of the "solar constant" vary from day to day, and that even at two stations as far apart as Mount Wilson (California) and Bassour (Algeria) there is a very well-marked correspondence between the values derived at these stations, so that the action of local atmospheric effects is not the cause of the fluctuations. Prof. Abbot considers the outstanding variation to be due to a real fluctuation of the solar constant. In order to investigate this question further, it was decided to make an extended series of observations at Helwân, and this was commenced at the beginning of last year. The account of these measures is given in this paper. For the statistical purpose of comparing the results obtained with those at Mount Wilson, the highest precision of individual observations is not required, but an extended series of measurements uniformly treated is of the greatest value. For this reason pyrheliometer measures of the total energy alone were made. The communication describes the method employed, the reduction of observations, and the results secured. While the value of the radiation derived from the Smithsonian Institution observations at Mount Wilson is 1.932 (mean value of 696 observations taken at Washington, Mount Wilson, and Bassour during the period 1902-1912), the Helwân mean value derived is 1.782. The latter value is considerably less than the Smithsonian mean value, and the cause of the difference is dealt with by the author in subsequent paragraphs. Finally, evidence for the fluctuation during the period of observation is dealt with, and it is concluded that while some of the deviations are probably due to real fluctuation, no conclusive decision can be reached until the Mount Wilson results can be compared.
THE BRILLIANT FIREBALL OF SUNDAY, MARCH 28.
ETWEEN March 21 and 29 eight large meteors were observed, but by far the most brilliant object among them was that of March 28, 7.47 p.m. Its flight was witnessed by many hundreds of persons from the southern parts of England, as well as from the English Channel, France, and Belgium.
As viewed from London, the meteor sailed slowly along a few degrees under the stars Sirius and Rigel, and further westwards to possibly beyond y Eridani. Mr. H. P. Hollis saw the meteor from a place about three miles due east of the Royal Observatory, and estimated its duration of flight as between five and six seconds. He did not see the beginning, and it was difficult to trace the exact point of extinction owing to trees behind which the object passed.
Mr. G. P. B. Hallowes was in his observatory at
East Howes, Bournemouth, with an astronomical friend, Mr. C. Gregory, when the meteor burst out in the southern sky. It moved from the region of Hydræ to near Rigel at about the place of v Leporis. It passed a little above Sirius. Brilliancy far exceeded Venus, and its duration was from three to four seconds. A trail 5° or 6° long followed the nucleus, and the latter burst into fragments at the end. The front of the head was yellow, the rear part red. Diameter, about 15', or half that of the moon.
Mr. A. King saw the meteor from Scunthrope, Lincolnshire, and from this northerly position its apparent path was very low, being from about 117° 31° to 98° - 32°. The brightness was estimated equal to Sirius, the colour yellow-green, and duration 7 seconds.
Mr. H. Rollason, of Montgomery, Wales, states that the meteor flamed out on the western sky, moving from S.E. to N.W., bursting twice, and enduring altogether five to six seconds. Many other observations have been received or published in the daily papers. As usual, there are discordances, but it is not difficult to derive a real path fairly consistent with the data.
The radiant point is indicated at 1920+4°, or possibly 220° 14°, low in the eastern region of the sky. The height of the object was from about 71 to 23 miles along a path of 175 miles from over the neighbourhood of Vire in France to the English Channel, about 60 miles south of Eddystone. Velocity, 24 miles per second. The meteor seems to have been directed from a radiant comparatively unknown in March, but in April, contemporary with the Lyrids, there is a rich shower of slow and brilliant meteors from 200°+8° near o Virginis.
The recent fireball must have passed almost vertically over Jersey, and from the Channel Islands and western parts of France it created a splendidly luminous effect. As viewed from Bournemouth the apparent size of the pear-shaped head of the meteor was considered to equal half the moon's diameter, which, from the distance of the object, would imply a magnitude of of nearly two-thirds mile. This must have enormously exceeded the actual dimensions of the stony, or metallic, material composing the meteor. When undergoing combustion, the flame and expanding gaseous vapours from meteors give a vastly exaggerated idea of their real size. It must be very rare that a fireball exceeds one or two feet in the diameter of its material.
I have ascribed a flight of 175 miles to the recent fireball, but it may have been much longer than that. Many of the observers did not detect the object until it had developed considerable brilliancy. The moon was nearing the full at the time of its appearance, but the meteoric visitor startled some of the spectators with its astonishing lustre. W. F. DENNING.
THE INSTITUTE OF METALS.
VOLUME XII. of the Journal of the Institute of
Metals, representing the work of the Institute during the second half of 1914, has just appeared. This is one of the first volumes of proceedings to appear since the outbreak of the war, and it indicates that the Institute of Metals has been able to pursue its activities, except for the fact that the autumn meeting which was to have taken place at Portsmouth early in September had to be abandoned. An interesting series of papers, however, are fully discussed by correspondence in the Journal. One of the most interesting from the scientific point of view is the paper by Mr. O. F. Hudson on the critical point at 460° C. in zinc-copper alloys. Mr.
Hudson brings forward evidence, which appears to be quite conclusive, that the interpretation of this point as marking the decomposition of the B phase of brass into a+y, which has been elaborated by Prof. Carpenter in a series of papers, is erroneous, and that the phase merely undergoes a polymorphic change from ẞ to B. A striking method of proof adopted by Mr. Hudson is that of preparing a series of alloys in a single piece of metal by the method of superposition. By superposing molten zinc on a layer of solid copper, the alloys can be formed at a temperature below 460° C., and yet a phase which corresponds to ẞ makes its appearance. If what Carpenter has called "apparent 8" were really unstable below 460° C., it could never be produced synthetically below that temperature.
Equally interesting from another point of view is the paper, and resulting discussion, by Mr. Arnold Philip dealing with the causes of corrosion in condenser tubes. In the recent Report to the Corrosion Committee of the Institute of Metals, Dr. Bengough and Mr. Jones had been led to reject entirely the view that particles of foreign matter, such as coke, which might set up local electrolytic effects, could thereby accelerate local corrosion and produce "pitting." Mr. Philip traverses this conclusion, and suggests that it was reached on insufficient evidence, while he adduces positive evidence to show that particles of coke can cause local pitting. While such divergence of views among those studying these matters is somewhat unfortunate from the point of view of the practical man seeking guidance for his practice, it serves to show the great need which exists for the further exhaustive investigation of such fundamental questions, and at the same time demonstrates the useful work of the Institute of Metals in encouraging such work and providing a meeting ground for full and-fortunately-dispassionate discussion.
Further papers of special scientific interest are those by Mr. S. W. Smith on the surface tension of molten metals, by Mr. Phelps on the effect of hydrogen on the annealing of gold, and by Messrs. Bengough and Hanson on the tensile properties of copper at high temperatures. In a Note" Prof. Huntington also deals with the tensile properties of metals at high temperatures, but while Bengough and Hanson find in their results strong support for the theory that the crystals of a metal are held together by something of the nature of an amorphous cement, Huntington urges somewhat vague objections to that view..
Another "Note," contributed by Prof. Carpenter, deals with "The Extraction of Native Cooper at Calumet, Lake Superior "; while in itself not uninteresting, it is difficult to understand why this note has been included in the Journal of the Institute of Metals, since it deals with a subject outside the scope of its work and coming well within that of the Institution of Mining and Metallurgy. Although unimportant in itself, such a departure from accepted limitations causes confusion when references have to be looked up.
squids, all of which are very fully illustrated, Mr. C. Ishikawa describes a new species of the genus Enoploteuthis from the Japan Sea, while in the second Messrs. Ishikawa and Wakiya treat of a number of fragments of a gigantic species taken from the stomach of a sperm-whale. The latter is identified with Moroteuthis robusta, of which it forms the fifth known example; in the third article the lastnamed writers describe a new species of the same genus under the name of M. loennbergi.
In an article, illustrated by one coloured and four black-and-white plates, in the February number of the Entomologist's Monthly Magazine, Dr. T. A. Chapman describes the larva of the butterfly Everes argiades, with figures, not only of the entire caterpillar, but also magnified representations of the shed skins at various stages of development. In the same issue Dr. D. Sharp continues his account of the beetles of the group Holophorini, dealing in this instance with the structure in the genital tube known as the ædeagus, which, as exemplified in Meghelophorus aquaticus, is described in great detail.
Aberrant modes of reproduction in certain wellknown insects, such as the blue oil-beetle, the parasitic genus Stylops, and the vine-phylloxera, form the subject of an illustrated article by Mr. W. M. Scheyen in the January number of Naturen. A continuation is promised.
Writing in the January number of the Zoologist of non-sexual reproduction in sea-anemones, as observed at the Millport Marine Biological Station, Mr. R. Elmhirst remarks that although division is usually completed in a few days or weeks, especially among the members of the genus Anthea, yet that he has seen instances in which "double" individuals of Actinoloba showed no change during a period of several months. He also records a case in which an Actinia with two complete discs, mouths, and rings of tentacles retained the same form for close on four years in an aquarium. Possibly, of course, the somewhat unnatural conditions in such an environment may be a factor in these cases.
In Spolia Zeylanica, vol. x., part 36, Mr. A. Rutherford mentions that the females of a "glowworm" (Dioptoma adamsi), in addition to the usual terminal light, have a number of other luminous points, apparently arranged in ten transverse rows. Somewhat similarly situated points of light also occur in the smaller males.
In the February number of the Irish Naturalist Mr. A. W. Stelfox gives a list of land and fresh-water molluscs from the Dingle Promontory, Kerry. Seventy-four indigenous species are recognised.
PROBABLY the first point that will strike the
student of mineral statistics when he sees the report now before us is the extreme dilatoriness of our Home Office. This report, which covers the mineral statistics of the world up to the end of 1912, was not published until the end of 1914; the Chief Inspector endeavours to excuse this delay by a reference to the lateness of the publication of official foreign statistics, but it is a significant fact that a private firm in the United States of America issued a large volume covering the world's mineral statistics for 1913 in July last, so that our own official production is no fewer than eighteen months behindhand. Statistics of mineral production are practically valueless unless they are published promptly, and all the 1 "Mines and Quarries. General Report with Statistics for 1912." By the Chief Inspector of Mines. Part iv., Colonial and Foreign Statistics,
information under this head afforded by the present publication has been common knowledge amongst all those interested for so long that it no longer presents any features capable of attracting attention.
The most interesting portion of the present report is accordingly that portion that deals with the labour employed in the world's mineral industry. It is shown that the number of persons engaged in this industry exceeded 6 millions, more than one-third of whom were employed in the British Empire. It is interesting to note that more than one-half of this number was employed in coal mining, and as coal mining in different countries is more readily comparable than any other class of mining, because the conditions under which it is carried on present closer points of agreement, it may be profitable to compare briefly the labour statistics. Out of a total production of 1,250,000,000 metric tons of coal in the whole world, Great Britain alone produces 264,600,000 tons and the whole British Empire 314,500,000 tons, or about a quarter of the whole output. The other large producers are the United States with 484,900,000 metric tons; the German Empire, 255,800,000; AustriaHungary, 51,700,000; France, 41,100,000; Russia, 31,300,000; Belgium, 23,000,000; and Japan, 19,700,000. It is curious to note that, with the exception of the United States, this list includes all the important nations engaged in the present war. The producing capacity of the miners engaged in this industry in metric tons per worker per annum is shown in the following table
230 United States 535 German Empire...
It will be seen that with the exception of India, where the labour is almost exclusively native, no part of the British Empire can show so low an output per head as does Great Britain itself, whilst of foreign countries it is only the smaller producers that rank worse than ourselves. In part, this small production is no doubt due to the fact that so many of our thicker and more easily wrought seams are to a large extent worked out, and that we are therefore compelled to work the thinner seams, from which a smaller output per man is necessarily produced. This drawback should, however, have been largely offset by the use of mechanical means for cutting and transporting coal, and it is difficult to avoid the conclusion that the low output is due to the restrictive policy covertly, if not overtly, encouraged by the Trades Unions.
It is some satisfaction to find that British coal mining is conducted with a great regard for the safety of the men engaged in this occupation. The deathrate per thousand workers employed is given as follows:
It ought to be added that the above statements are calculated from the data tabulated in the report in question, which gives the figures for the various countries as though they were obtained in the same way, and therefore strictly comparable, which is far from actually being the case. Different countries use different methods of determining their mineral production, the number of men engaged in the industry and the number of deaths due to it, and the figures given are not therefore strictly comparable, though they may be expected to give a rough standard of comparison. One of the objects aimed at for many years by statisticians interested in mineral production was to get an international understanding as to the basis on which all these figures were to be determined, but now that Germany has in a few months destroyed the work of many years of European civilisation, and by her own relapse into barbarism has dragged all other nations down with her, any prospect of agreement on such minor international questions appears to be quite hopeless. H. L.
REPRODUCTION AND HEREDITY.
PROF. J. A. DETLEFSEN (University of Illinois) has made an important contribution to our knowledge of "Mendelian inheritance by his Genetic Studies on a Cavy Species Cross" (Carnegie Institution, Publication No. 205, 1914). The research -begun by Prof. W. E. Castle-is of interest as affording information from the crossing of two distinct species, for the wild Brazilian cavy (Cavia rufescens) is apparently sharply distinct from the common domestic guinea-pig (C. porcellus). The sterility of hybrid animals is known to be a rule admitting of many exceptions. In the experiments with cavies here described, crosses between C. rufescens males and C. porcellus females gave completely sterile male and fertile female hybrids. By mating the female hybrids with porcellus males, quarter-wild hybrids were obtained, again sterile males and fertile females; but by repeated back-crosses of female hybrids to porcellus males, individuals with increasing fertility were obtained. "Fertility seemed to act like a very complex recessive character; for the results obtained were what one would expect if a number of dominant factors for sterility were involved, the elimination of which would give a recessive fertile type." The paper is noteworthy because skeletal characters of the parents and hybrids are figured and compared, in addition to the usual external features, such as coat-colour.
A case of sex-limited inheritance in plants is discussed by Mr. G. H. Shull, who has made crosses between the typical Lychnis dioica and its variety angustifolia (Zeitschr f. indukt. Abstammungs u. Vererbungslehre, xii., 5, 1914). The narrow-leafed form is a recessive which reappears in half the males of the F, generation. All the F, broad-leafed males are heterozygous for the broad-leaf factor, while of the females half are heterozygous, half homozygous for this factor. As regards sex, the female Lychnis is a homozygote and the male a heterozygote.
Dr. Raymond Pearl continues his observations on the reproductive organs of domestic fowls. In a paper on the effects of "Ligation, Section, or Removal of the Oviduct" (Journ. Exper. Zoo., xvii., 3, 1914), he states that these operations have no injurious effect on the growth of the ovary, and that after removal or closing of the oviducal funnel, eggs are passed into the body-cavity, where, if not absorbed at the peritoneal surface, they may cause "serious metabolic disturbances." In the Journ. Biol. Chemistry (xix., 2, 1914) Dr. Pearl informs us that injection of the
desiccated fat-free substances of a cow's corpus luteum into a laying fowl at once inhibits ovulation. The possible practical importance of studies in heredity is shown by a short pamphlet from the annual report of the Maine Agricultural Experiment Station for 1914 on improving egg-production by breeding, and by a Bulletin (No. 110) of the U.S. Department of Agriculture (Bureau of Animal Industry), in which Dr. Pearl, with Dr. F. M. Surface, gives "A Biometrical Study of Egg-Production in the Domestic Fowl."
BACK TO LISTER.1
days, the presence of a wound was almost certain to lead to suppuration of a serious, if not a dangerous
Old Glasgow students speak of Lister contemplating a simple fracture of the leg; the muscles torn and pulped, the limb swollen and shiny, black and blue, and pointing out to them that all this destruction of tissue and extravasation of blood would be surely and safely dealt with by the kindly influences of nature; but that the admission of the air through the smallest wound in the skin would completely change the prospect; the extravasated blood would soon stink, the injured tissues-bone and muscle-would die, and
WHEN Sir James Crichton-Browne, amongst suppuration would take place, which might possibly
whose many charms is a singular felicity of phraseology, invited me to undertake this task, he kindly supplied the title. It sounded rather startling, but as I could not think of a better, I humbly accepted it. It shows that I have no great discovery to announce, no new theory to propound, but only to take you back over old, well-trodden ground, to try to interest you in very technical matters, and to suggest that, in this particular case, reaction has overstepped the bounds of moderation, and that, as in many other fields, the most modern ideas are not always the best.
I will not trace the various steps by which Lister was led to his conclusions about the causes of suppuration and hospital diseases, nor draw a lurid picture of the deplorable mortality from these diseases before the introduction of the antiseptic system of treatment. I must, however, give you a short account of his first antiseptic method, which was founded on the discoveries of Pasteur, and explain in what way and for what reasons he afterwards modified it. If I succeed in making this clear it will be easy to understand how the relinquishment of much that he at first considered essential, but which later discoveries proved to be superfluous, led others to give up still more -much more than he ever considered it prudent to do. It will then be maintained that what he feared has come true: that the results obtained to-day, good though they are, are not so good as they would be if we were to return, perhaps not altogether, but almost, to those simpler and safer methods which Lister employed at the end of his active career.
Let us begin by trying to place ourselves in Lister's position during the years preceding 1865, when the writings of Pasteur were first brought to his notice. It was that of every thoughtful surgeon in those days. Of all the dealings of Providence with men—remember I am speaking of sixty years ago—not the least mysterious appeared to be the ordinance that the lifegiving air, heaven's blessed breeze, without which life cannot be maintained for more than a few minutes, and on the purity of which man's vigour depends, should carry in some unexplained way the seeds of death and disease, being one day the doctor's greatest friend and the next his deadliest foe.
Physicians were quite sure that the acute specific fevers, such as scarlet fever and measles, were carried on the wings of the wind, and few had any doubt that cholera was borne by the same vehicle. Surgeons were equally certain that erysipelas should be placed in the same class as the acute specific fevers and that the suppuration of wounds depended upon the same agency. It seemed quite obvious, to anyone who thought about the difference in the behaviour of simple and compound fractures, that is, fractures with unbroken skin and those which are complicated by the presence of a wound. Except for this complication the fractures might be identical, but, in pre-antiseptic 1 Discourse delivered at the Royal Institution on Friday, March 12, by Sir R. J. Godlee, Bart., K.C.V.O.
infect the whole system. It did not enter into the mind of anyone, therefore, to doubt the morbific influence of the air. It was one of those things which appear so obvious that for a time they form the very foundations of belief, such as that the earth is flat and that the sun rises, matters which in more barbarous times laid sceptics open to the rigours of the Inquisition.
This was still the universal belief when Pasteur's discoveries were made known. Pasteur put the finishing touch to the work of many observers, who, during the first half of the last century, had been striving to find out what there was in the atmosphere which gave rise to fermentations of all sorts, and amongst others to that form of fermentation known as putrefaction. So long as fermentation and putrefaction were looked upon as chemical processes it was natural to suppose that one of the gaseous constituents of the air was the cause. But clear thinkers, like John Hunter, saw that this could not be the case.
There are two surgical conditions that prove this :(1) If a rib be broken and a sharp fragment injures the lung, large quantities of air may pass from the lung into the pleural cavity, but if the lung be healthy, decomposition never occurs in the putrescible fluid that is always present in the pleura in small quantity.
(2) If air passes into the cellular tissue of the body, as it sometimes does after the same accident, or some other injury of the air passages, large portions of the body may be distended by it to an extent that appears alarming. But again, as the air is effectually filtered on the way, decomposition does not occur and the evil result is only a temporary mechanical one.
Investigators, therefore, began to think that the cause of fermentation must be something solid and possibly living; something so small that it eluded their highest magnifying glasses, and so they adopted different lines of attack.
Some calcined the air, some filtered it, some passed it through causic fluids. There was an old French confectioner named Appert-Citoyen Appert, in the time of the Republic, who anticipated by many years the work of our modern fruit preservers. He succeeded in preserving all sorts of focd in well-corked bottles by boiling them for various lengths of time according to the particular article he was dealing with; and his results were so nearly uniform and so remarkable, from an economic as well as from a scientific point of view, that they attracted the attention of the French Minister of the Interior in 1810, and also of the Académie Française.
Unscientific as these observations were, they gave an impetus to the work of chemists and biologists who carried out an enormous number of really scientific investigations in consequence. These were repeated by Pasteur, who made countless others of his own, of marvellous ingenuity. The results of his labours in this particular field before 1865 may be given in a tabular form. He showed that :
(1) Putrefaction is a species of fermentation.
(2) It is caused by the growth of micro-organisms and does not occur independently of them.
(3) The micro-organisms that produce fermentation and putrefaction are conveyed by the air on the dust that floats in it.
(4) These micro-organisms can be destroyed by heat and other agencies, or separated by filtration.
(5) Certain recognisable organisms produce definite and distinct fermentative processes.
(6) All of these organisms require oxygen. Some of them flourish only in the presence of free oxygen (aerobic), others only in its absence (anaerobic). The latter acquire their oxygen from the bodies which, by their growth, they are causing to ferment or putrefy. (7) Many natural animal and vegetable products have no tendency to ferment or putrefy even in the presence of oxygen, if collected with proper precautions and kept in sterilised vessels.
(8) Spontaneous generation has never been observed to occur, and thus may be regarded as a chimera. Now it will be observed that Pasteur's work presented Lister with two great fundamental facts.
(1) That putrefaction is caused by germs which can be destroyed by heat and chemicals and separated by filtration.
(2) That germs are carried by the dust in the air. It is true that both Pasteur and Lister did not fail to recognise that if the air carried the germs it must deposit them upon the surface of everything, and that therefore the surface of every solid and the whole of every liquid must be, or might be, infectious. It is also true that Lister bore this in mind, and acted on the assumption that it was true from the very first. But still it was the air to which he paid and directed most attention-more attention, as we shall see, than it deserved. He probably did not recognise, he certainly did not say, that his precautions with regard to other sources of infection were far more important than those which he took with regard to infection from the air.
The sceptics and cavillers, the believers in spontaneous generation, kept saying, "Show us your germs in the air." They did not doubt that organisms were found in putrefying substances, they could not do that; but they said that they might be accidental, the result of putrefaction, not the cause of it, and asked for proof that germs existed in the air. Pasteur had tried to meet this objection by filtering the air through gun-cotton, which he afterwards dissolved and submitted the solution to the microscope. There were certainly objects which he was satisfied were germs, but the doubters were still unconvinced.
A few years later, about 1869, John Tyndall, whose eloquent addresses on "Dust and Disease were listened to with breathless attention in this hall, succeeded in showing to the naked eye of untrained amateurs, the existence of, and the amount of, floating dust in any given sample of air, by passing through it a concentrated beam of light. Next he showed that, if the air was left undisturbed, say in a glass flask, the dust settled, and there was nothing for the beam to illuminate. Then he produced the same result by filtering the air, or by raising to a great heat a piece of platinum wire passing through the flask which burned up the dust. Finally, he proved, by a series of charmingly simple experiments, that what he called optically pure air was incapable of setting up decomposition in putrescible fluids, whereas optically impure air invariably caused them to decompose.
Most of these facts were known to Lister in 1865. All the evidence pointed in the same direction; and therefore, stated in the simplest way, the problem seemed to be to kill the germs which might have gained access to the wound before it came under
treatment, and to prevent the air from carrying in others afterwards.
He first applied what he now called the antiseptic principle to compound fractures, injuries which, above all others, were liable to be followed by those hospital plagues-pyæmia, erysipelas, and hospital gangrene.
He had to choose between the three recognised methods of excluding the germs-filtration, calcining, and chemical antiseptics and he naturally selected the last as the most convenient. The first antiseptic he tried was carbolic acid, and as the crude sample he first worked with was insoluble in water he used it undiluted.
His plan for treating compound fractures was, after cleansing the wound, to sponge the whole of the raw surface with this undiluted crude German creosote in order to destroy the germs introduced by dirt or other foreign material at the time of the accident, or that, as he supposed, had been carried to it by the air. The carbolic acid mixed with the blood, caused an antiseptic crust, which he fortified by covering it with a thin piece of block-tin, and this crust effectually prevented the access of unpurified air to the wound; for he left it undisturbed for days or weeks and painted the outside with more of the undiluted acid from time to time.
I wish to impress upon you that in the earliest dressings he used a very strong antiseptic and did his best absolutely to exclude the air, and it is important to note that his results were strikingly good, in spite of the fact that the undiluted acid did actually cause a certain amount of superficial sloughing-or death of the tissues-in the parts to which it was applied. As time went on a purer carbolic acid was obtained which dissolved in water, so he abandoned the caustic undiluted acid in favour of a saturated watery solution: I part to 20.
He soon extended the treatment, first to abscesses and then to ordinary operation wounds. The old antiseptic crust was soon given up, and various dressings containing carbolic acid or other antiseptics were employed instead. But for a long time he was so anxious about the air that he irrigated the wound with a solution of carbolic acid in water throughout an operation, and took the most elaborate precautions against allowing any air that had not been submitted to the influence of carbolic acid to reach the wound at the changing of the dressings. He used to say that merely taking out a drainage tube without antiseptic precautions involved a serious risk, because the air which rushed in to take its place might carry some speck of dust and a germ along with it.
In his most palmy days, when he was professor of clinical surgery at Edinburgh (1869-77), and Edinburgh was for the time the surgeon's Mecca, he introduced the spray in order to deal still more effectually with the air. In its most highly developed form the steam spray-producer threw a copious vapour, which was supposed to contain one part of carbolic acid in forty of water, that surrounded the whole region of the operation, and, if the room were small, might even fill the whole apartment with a pungent vapour, to the great discomfort of all concerned. He thought at the time that the momentary contact of the dust with the particles of carbolised water in the spray, or the carbolised atmosphere between the drops would be enough to destroy the germs; but in after years he owned that such a result was impossible.
At this period, though he was still using strong antiseptic lotions very freely, his results were yet more remarkable; and in the meantime, relying on the antiseptic principle, he was doing new operations which, without it, he would have considered to be altogether unjustifiable.