Obrázky stránek

very unhealthy. This district was formerly part now added in excess, and the mixture gently of the dominions of the rajah of Gurhwal, was boiled over a spirit lamp for a few minutes; if overrun by the Goorkhas in 1803, and in 1815, sugar is present, a precipitate of a reddish or during the Nepaul war, was invaded by the yellowish brown (suboxide of copper) will be British, who suffered great loss here, and who, thrown down, otherwise the precipitate will be after the expulsion of the Goorkhas, kept pos- black (common oxide). In Moore's test, a little session of the territory.-Deyra, the principal of the suspected urine is mixed in a test tube town of the district, is situated in the midst with about fits volume of liquor potassæ, and of dense mango groves, at the intersection of 2 the mixture boiled for 5 minutes; if sugar be routes of trade, 2,369 feet above the sea. present, the fluid will acquire a brown hue,

DEZFOOL, DEZFUL, or DEZPHOUL, a city of otherwise it remains unchanged. A 3d test is Persia, in the province of Khoozistan, on the founded on the fact that diabetic urine rapidly eastern bank of a river of the same name; pop. undergoes fermentation when mixed with a little estimated at 15,000. It is the principal mart yeast and kept in a warm place. The sugar of the province, and has a fine bridge of 22 to which diabetic urine owes its peculiar proparches, said to have been built by command of erties exists in the form of glucose or grape the celebrated Sapor. About 10 miles S. W. sugar. This is present in all proportions, from from the city are mounds of ruins which cover a mere trace to 30, 50, and even 134 parts in the site of the ancient city of Susa.

1,000. The quantity of solid matter thus drainD'HILLIERS. See BARAGUAY D'HILLIERS. ed from the system is very great; Dr. Thomas

DIABETES, GLUCOSURIA, DIABETES MELLI- Watson estimates it on the average at 11 lbs. per TUS, GLUCOHÆMIA (Gr. daßalvw, to pass through), day, but it sometimes amounts to many times a disease characterized by an excessive secretion this quantity; and it is this drain of solid matter, of saccharine urine. Though disease marked together with the large amount of urine passed, by diuresis and attended with wasting of the which gives rise to the constant thirst and the body was frequently spoken of by earlier au- enormous appetite of diabetic patients. Early thors, Willis (1659) was the first who noted the in the disease, as was before observed, the symp distinctive character of the complaint, the pres- toms are not well marked; when the complaint ence of sugar in that fluid. Since his time is established, and the large excretion of urine diabetes, which is not a very rare complaint, begins to attract attention, the patient come has been frequently made a subject of study, plains that despite his excessive appetite he yet still a great deal of obscurity envelops its grows thinner and weaker; the mouth is pasty, causes, its essential character, and its treat- the skin dry and hard, the bowels constipated. ment. The invasion of diabetes is commonly The digestive functions, at first normal, become insidious. The attention of the patient is per- deranged; the patient is troubled with heartburn, haps first attracted by the quantity of urine with a feeling of weight and pain in the epigashe passes and by the frequent calls to void it, trium, sometimes with vomiting. The strength or he notices that while his appetite is greatly declines, the patient becomes emaciated, the increased he is growing weaker and thinner. generative functions are impaired or lost; vision If the urine be now examined, it is found to be often becomes dim, the gums are spongy, there not only greatly increased in quantity, but some- is tenderness and swelling about the orifice of what changed in appearance; it is paler, trans- the urethra, the memory and intellect fail, parent when first passed, and assumes on stand- and the temper becomes irritable. In the ing an opalescent tint like the whey of milk or a course of the disease pulmonary consumption is solution of honey in water. It has no odor, or very apt to supervene and carry off the patient. a somewhat aromatic one, compared by some to Toward the last, diarrhea, fetid breath, effusion that of new-made hay, by Dr. Watson to that into the great cavities, and ædema of the ex. of a room in which apples have been kept. If tremities, precede death. Diabetes is essentially kept for a few days at a moderately elevated a chronic disease, lasting often many years; temperature, instead of acquiring an ammonia- it is also an obstinate and intractable one, al. cal odor like ordinary urine, it has a sharp vinous though most of the cases seem benefited by smell, and will be found to be acid rather than treatment, and sometimes it would appear to alkaline. The urine has commonly a decidedly be completely cured.— Treatment. In the besweet taste; drops of it upon the patient's linen ginning of the present century Dr. Rollo found or clothes stiffen them like starch, and some- that the amount of urine in diabetic patients times leave on evaporation a powdery efflores- as well as its sweetness was very much dimin

The specific gravity of the urine is ished by confining them to an animal diet. greatly augmented; instead of being from 1.015 When the ready conversion of starch into grape to 1.020, as is commonly the case, it ranges from sugar became known, this was assumed to be 1.025 to 1.050 ; M. Bouchardat reports it even the origin of the sugar, and the benefit derived as high as 1.074. Two or three simple and easily from an exclusively animal diet was thus explainapplied tests are sufficient to render the presence ed. Unfortunately, few patients have the

reso. of sugar certain. In what is called Trommer's lution to restrict themselves for any length of test, å drop or two of the solution of the sul- time to such a diet, and even when persevered in phate of copper is added to a little of the urine it is found to be merely palliative. The experiin a test tube; a solution of caustic potash is ments of O. Bernard have thrown a new light


upon the subject. He has ascertained that sugar of the first importance in practical medicine, is a normal secretion of the liver in all classes

of and requires all the acuteness and discriminaanimals, carnivorous as well as herbivorous; that tion of the physician; without a correct diagnoit takes place in the liver of the fætus as well sis, treatment must be empirical and hazardous. as in that of the adult; that irritating the origin A mere acquaintance with the symptoms of of the 8th pair of nerves in the 4th ventricle each disease cannot enable the physician to increases the secretion of sugar, producing an make his diagnosis. These symptoms are given artificial diabetes. In a state of health the nor- briefly under the different diseases ; diagnomal secretion of sugar poured into the circula- sis will be treated here only as a branch of gention by the hepatic veins is rapidly decomposed eral pathology. Of the symptoms of disease, and excreted by the lungs; when the amount is some are characteristic and pathognomonic, increased by disease, the excess passes off by the essential and always present; some are common kidneys. Under the influence of diastase, sugar to other diseases, and are of value only when is likewise formed from the starch of the food taken in connection with the former class. Exin the process of digestion, as a necessary pre- amples of the former are the eruptions of the liminary to its absorption. When diabetic pa- exanthemata, and the mobility of the ends of tients are placed upon an animal diet, this source broken bones; of the latter, the increased freof supply is cut off

, and the amount of sugar in quency of the pulse, heat of the skin, and thirst, the urine is diminished, but it is still present, common to many different diseased states. А since the liver keeps up the supply. M. Mialhe, physician must know how to examine and interinfluenced by the theoretic belief that sugar in rogate a patient, to use his own senses of sight, the course of the circulation is decomposed hearing, and touch, to sift the statements of atunder the influence of the alkalinity of the tendants, to weigh justly positive and negative blood, and that in diabetes the blood is deficient signs; which he can only learn by a knowledge in alkalinity either positively or relatively to of anatomy and pathology, by experience at the the amount of sugar contained in it, recom- bedside, by an acquaintance with the physiolomends the use of the bicarbonate of soda in gical functions of organs, and by familiarity with large doses. He recommends } a dram to be the physical examinations of the sick. His fintaken 3 times a day, morning, noon, and night; gers must be educated to a sensibility equal to this is gradually increased until from 180 to 270 that of the blind man's ; his ear, armed with grains are taken in the course of the day. In the stethoscope, must hear the first footsteps of addition, the patient is directed to take Vichy disease in the heart and lungs, or the first murwater with his meals, and is recommended to mur of life in the gravid uterus; his drink lime water to the extent of 2 or 3 pints by the microscope, must follow the course of daily. He is permitted to indulge in the or- morbid growths back even into the primary dinary variety in his diet, but the quantity structure of the cell; he must press, percuss, and of farinaceæ is reduced } or at least . Flan- measure with the greatest delicacy and exactnel is ordered to be worn next the skin; the ness; he must be familiar with chemical reacvapor bath is administered 2 or 3 times a tions, in order to detect and neutralize poisons, week. By these means M. Mialhe reports & and arrest the formation of dangerous precipinumber of cases to have been cured. Dr. A. tates in the nutrient and excrementitious fluids. Clark of New York (New York " Medical and By this manner of interrogating and examining, Surgical Journal,”. Jan. 1859) reports several both by physical and rational signs, every organ cases of diabetes either cured or greatly bene- and function, the seat, extent, and nature of the fited by the use of bicarbonate of soda and of disease are ascertained; and it is in making a blisters to the nape of the neck. Dr. Clark ad- diagnosis, more than in the treatment, that one ministered the soda in doses of 11 grains, to be physician excels another; for though a blind taken as frequently as could be borne until the exhibition of remedies may occasionally be sucurine was rendered alkaline or the stomach was cessful in arresting disease, it must be obvious nauseated. Beside the alkaline treatment, the to every reasoning mind that a knowledge of means principally relied on have been restrict- the disease is the first and great essential to its raing the quantity of farinaceous matter in the tional treatment. There are many causes which patient's diet as far as possible, indulging him render the diagnosis of disease difficult and unin watery vegetables (spinach, turnips, cabbage, certain—such as the advanced stage at which &c.) rather than in bread or potatoes, and the many affections are seen; the unusual predomiuse of opium. This last remedy allays the ner- nance of certain merely sympathetic phenomena, vous irritability of the patient, and diminishes which mask the primary lesion; the occurrence the thirst and the amount of the urinary secre- of new and anomalous types of disease; the tion.

complication with other diseases; and the tender DIAGNOSIS (Gr. Olayuwois, examination, de- age, imbecility, insanity, dissimulation, and decision), a term in medicine indicating that de- ceit of patients. It must be evident from this, partment of pathology whose object is the dis- what a union of rare faculties and varied actinguishing of diseases by the knowledge of their quirements is necessary to enable a physician to special pathognomonic signs. To distinguish a make a correct diagnosis of disease; and also disease under all its various forms, and when that, without this primary result, all speculation complicated by symptoms of other affections, is as to its progress and termination is mere con

eyes, assisted



jecture, and all treatment blind and base empi- hour upon the face of the card. This dial has ricism. The French school of medicine is famous the advantage of being portable. Dials of the for the stress it lays on diagnosis; and students first kind, of a rude nature, may be made portfrom other parts of Europe, and more especially able by baving the rod and the dial surface light from the United States, flock to Paris to acquire enough to be balanced upon a compass needle. the elements and practice of this most essential Beautifully engraved sun dials, for the regulating branch of their profession.

of clocks, are manufactured by the electrotype DIAGORAS OF MELOS, surnamed the Athe- process in copper.-The term dial is also applied ist, a Greek philosopher, lived in the time of to any graduated surface, such as a clock or watch Socrates and Aristophanes, but neither the date face, upon which time is marked out. of his birth nor that of his death is known. He DIALLAGE (Gr. dallay, change, alteramust have removed from his native island to tion), a mineral of the augite family, so named Athens before the performance of the “Clouds" from its tendency to cleave in different direcof Aristophanes (424 B.C.), for he is alluded to tions. It is a variety of hornblende, in thin in that piece as one well known to the Athe- foliæ, of various shades of green, gray, brown, nians. He was a disciple of Democritus of and bronze colors, and is found in serpentine Abdera. He ridiculed the popular religion, and and greenstone. Its specific gravity is 3.25. attacked especially the Eleusinian mysteries, on Diallage rock, also called euphotide, is a comaccount of which he was accused of impiety pound rock of diallage and feldspar. (411 B. O.). Fearing the result of a trial, he DIAMAGNETISM. In the native magnet made his escape from the city. He was con- (an ore of iron) a peculiar force resides, which, demned to death by the court, and a price set if a mass of this body be suspended freely, turns upon his head. Notwithstanding this, after liv- or directs it into a line varying slightly from ing for a time at Pallene, he finally died at peace the course of a meridian on the earth's surface. in Corinth. His works are all lost.

The same end of the magnet being always diDIAL. Sun dials are among the most an- rected toward the north, this has been termed cient of human inventions, and, although some- its N. pole ; the opposite, its S. pole. Certain times said to have been invented in Lacedæmon, bodies, especially iron, brought near to a magwere more probably derived by the Greeks net, have the magnetic condition induced in from eastern nations. The dial of Ahaz, the them, the extremity nearest either magnetic king of Judah, is one of the earliest mentioned pole becoming a pole of the opposite name, that in the history of the East, and it is probable most remote a pole of the same name. This that the Jews learned the use of this invention result is in accordance with the law that like from the Babylonians. According to Wilkin- poles repel, while unlike attract each other. A son, “there are no indications in the sculptures soft iron bar, around which the electrical curto prove the epoch when the dial was first rent is made to circulate upon a coiled conductor, known in Egypt.” The modern improvements or helix, becomes magnetic for the time, but in artificial modes of measuring time are so loses its magnetism when the current ceases. great, that sun dials are now more a matter Small magnetizable particles, as iron filings, of curiosity than of use. They may be divided dusted upon a surface on which a magnet rests, into 2 essentially different kinds, one of which or agitated near it, become arranged in lines we may call geometrical, the other algebraical. which, between unlike poles that are presented In order to comprehend the first, we need only to each other, run across in straight lines, while observe, that if a rod or gnomon be placed par- about these on either side they form curves, allel to the axis of the earth, its shadow, con- making larger and larger sweeps into space. ceived of as a sheet of darkness passing in a The lines thus indicated have been named indg. plane from the rod on the opposite side of the netic curves, or lines of force. Until recently, sun, would swing steadily and equally round the the number of magnetic bodies was supposed to rod as a hinge, so long as the sun shone upon it. be very small. Becquerel

, in 1827, found that Upon whatever surface this shadow fell, whether a needle of wood playing freely on a pivot took horizontal, vertical, or inclined, its place could a direction across, not in, the magnetic curves; be used as a means of measuring time. And if and in 1829 Le Bailli also observed that bisupon this surface lines were drawn, marking muth repelled the magnetic needle. But the the place of the shadow at definite hours of the significance of these facts was not understood day, the rod might be made as short as we until an accidental discovery of Faraday, in pleased, reduced indeed to a single ball, held in 1845, led that philosopher into a full investigathe place where the extremity of the rod had tion of the phenomenon. In the course of his been, and the shadow of this ball would mark experiments on magnetic rotary polarization, he the time upon the lines of the shadow of the observed that a bar of so-called "heavy glass," rod. The other sort of dial, the algebraical, is suspended between the poles of an electro-magmore difficult to explain without the use of a net, moved, as soon as by the passage of the diagram. It is drawn upon a piece of card, to electrical current magnetism was induced in the which is attached a plumb line with a bead latter, into a position crossing the lines of force, sliding upon it; the card being held in such a or at right angles to the line joining the poles. manner that the upper edge shall point at the Terming the position assumed by a soft iron sun, its plane being vertical, the bead marks the bar which is lengthwise between the two poles,

1 1

or from one to the other, axial, Faraday gave to or diamagnetic, then, we mean that it is such the new direction assumed by the glass the name with reference to the medium in which it is tried; of equatorial. The glass was not merely thus and as this medium is commonly air, in which directed, it was repelled by either pole; and if, the magnetism of the oxygen dominates over the reduced to the form of a small mass or cube, it opposite property of the nitrogen, it is evident was thrown out of the line joining the poles to that some so-called diamagnetics are only relaone side or the other, it moved into the position tively such. With reference to the theory, Farof weakest magnetic action. This new-found aday now considers that the diamagnet is not property of certain bodies Faraday termed rendered polar, as is the magnet, but simply rediamagnetism; and in contrast with this, he de- pelled. Prof. W. Thomson has supposed the nominated the familiar form of magnetic action diamagnet to be simply a body less magnetizable paramagnetism. His experiments warrant the than air, but still polar. In this case it would conclusion that, with a sufficiently powerful move away for the more magnetic air, just as in electro-magnet, all substances whatever can be gravitation smoke makes way and ascends above shown to exhibit one or other of these proper- the more strongly gravitating cold air. Plücker, ties. Liquids and solutions were examined by Tyndall, and others adhere to a modified form being suspended in glass vials, the known influ- of Prof. Faraday's earlier view, namely, that ence of the glass being allowed for. Among the diamagnet is a body susceptible in greater or paramagnetic substances, by far the most pow- less degree of a double

polarity opposite in charerful is iron, then nickel and cobalt, and, in a acter to the double polarity of the magnet; or, slight degree, manganese, palladium, crown in the language of Ampère's theory, that as the glass, platinum, osmium, and some others. currents induced in soft iron are parallel to the Vacuum serves as zero in the scale. Then, currents in the inducing magnet or battery wire, passing from the less to the more diamagnetic so, in bismuth and other diamagnetics, the curbodies, are found arsenic, ether, alcohol, gold, rents are induced in contrary directions, so that water, mercury, flint glass, tin, heavy glass, an- these bodies become inverted magnets, and place timony, phosphorus, and, by far the most pow. themselves across the magnetic lines of force. erful, bismuth. Flames are diamagnetic, being DIAMANTINA, formerly Tejuco, a city of 80 strongly repelled by the poles that they di- Brazil

, and capital of the diamond district, situvide and pass up on either side, a descending ated in a valley of the province of Minas Geraes

, current of air going down in the middle. Most at an elevation of 5,700 feet above the sea; lat. organic substances are diamagnetic; wood, 18° 28' S., long. 43° 50' W.; pop. about 6,000. starch, sugar, leather, bread, and even animal It is built in the form of an amphitheatre, with tissues and blood, are instances. Oxygen, and wide, ill-paved streets, and handsome churches, perhaps nitrous gas, are the only gases which one of wbich, belonging to negroes from the are known to be ordinarily magnetic; and coast of Africa, contains an image of a black when it is added that oxygen loses in a degree, Virgin. Most of the houses are surrounded by though not wholly, its magnetic condition by pleasant gardens, and the environs of the city increase of temperature, it will be seen that are adorned with orange and banana trees. Tho the properties of this constituent of our atmo- climate is mild. The inhabitants are employed sphere probably have important bearings on the chiefly in the gold or diamond trade. production of terrestrial magnetism. Green DIAMETER, a straight line passing through glass is magnetic in consequence of the iron it the centre of a circle, terminated at each end contains; and to render wood ordinarily mag- by the circumference. Straight lines holding netic, it is only necessary to cut a chip of it an analogous relation to curves, such as the with a common knife. The magnetic condition conic sections, are also called diameters of those of any compound body is found to be determined by what may be called the algebraic sum DIAMOND (from adamant, and this from of the magnetic and diamagnetic powers of its Gr. a privative and dapaw, to subdue), so named constituents. Thus & compound or solution on account of its extreme hardness and indecontaining much iron will always be paramag- structibility, a gem distinguished above all other netic in greater or less degree; but if the iron precious stones for its brilliant lustre and hardbe blended with comparatively large amounts ness. It is met with in solid pieces of small of water and other diamagnetics, it may be size in alluvial deposits which are worked for brought to the neutral point, or the compound gold. In a few instances diamonds have been may be actually diamagnetic. Under all ordi- found attached to loose pieces of brown hemanary circumstances, the decidedly magnetic or tite, and one was discovered in a kind of condiamagnetic bodies give to combinations their glomerate rock, composed of rounded silicious own character. Another important point is the pebbles, quartz, and chalcedony, cemented togeinfluence of enveloping material. Certain sub- ther by ferruginous clay; but no positive knowstances that are repelled, and take the equatorial ledge is had of the particular rock in which position in air, are attracted and set axially in they originated, more than that it is one of those water; and even a solution of iron, magnetic belonging to the metainorphic group, which yield in air, if weaker than another solution in which gold. In the districts where they occur, à peit is immersed, will stand equatorially, and act culiar variety of light yellowish and white quartz as a diamagnetic. In terming a body magnetic rock, of laminated structure, called itacolumite,



is very commonly met with in these rocks. It tected from the action of the air may be beated is remarkable for its flexibility, and the peculiar to whiteness without injury. Exposed to the manner in which the long strips yield to a slight intense heat produced by a powerful Bunsen's pressure without parting, as if broken in their battery, or by a condensed mixture of carbonie interior. It is found in Brazil, and in Georgia oxide and oxygen gas, it fuses, and is converted and North Carolina, in the vicinity of the lo- into a mass resembling coke, and its specific calities that furnished the few diamonds discov- gravity is reduced in some cases to 2.678. Heatered in these states. In the Golconda district ed in the open air, it burns at the temperature the diamond is found in a black carboniferous of 14° Wedgwood, or about that of melting silboggy earth, in which the natives seek for it by ver, and is dissipated in the form of carbonic feeling with their feet. The belief is current with acid gas, thus proving its composition to be pure them that in this material it grows. In Brazil carbon. Its inflammability was suspected by diamonds have been found massive, in the form Boetius de Boodt in 1607, and in 1673 Boyle of pebbles. Their color is black; specific gravity, discovered that it was dissipated in vapor at a 3.012 to 3.416; composition carbon, with some- high heat. Its combustibility was first proved times 2 per cent. foreign matter. This quality is by the Florentine philosophers in 1694, by subvalued at 75 cents the carat of 4 grains nearly. jecting the gem to the solar rays concentrated The brilliancy and indestructibility of the dia- in the focus of the large parabolic reflector made mond attracted attention to it at very early for Cosmo de' Medici, when it burned with a periods, and caused it to be highly esteemed as a blue lambent flame. The experiment has been gem. It was long known in Asia before it was several times repeated by Sir Humphry Dary discovered in any other quarter; and the greater with the same speculum, and by Lavoisier, Mr. part of the supplies have been from that part of Tennant, and others, by different processes. Sir the world. Indeed, it was not until the early George Mackenzie made use of the diamond for part of the last century that diamonds were furnishing the carbon to convert iron into steel. known to exist elsewhere. The mines of Brazil The property of phosphorescence has been atwere then discovered, and from 1730 to 1814, tributed to the diamond after it has been exposed according to Baron d'Eschwege, their produc- to a heat approaching redness, or to the action tion was at the rate of 36,000 carats per annum. of the solar rays, especially the blue rays; and After 1814 it fell off greatly; but from 1845 to it has been stated that when the phenomenon 1858 there has been an enormous increase, the is produced by the latter method the effect constatistics of which have been already furnished tinues some time after the stone is removed in the article BRAZIL. In the gold region of Si- from the light. But this is not confirmed by late beria a few have been obtained, and within the authorities. Experiments conducted through last 20 years a few also in that of North Caro- several months in 1858 at Messrs. Tiffany and lina and Georgia. In Asia, the most noted lo- company's, of New York, failed to develop soy calities were the island of Borneo, Bengal, save negative evidence; and when they were and the famous mines of the kingdom of Gol- renewed in January, 1859, for the purposes of conda in Hindostan. The city of this name was this article, they were abruptly terminated the repository of the diamonds collected in the through the carelessness of a workman, by the territory of the kings of Golconda. These mines, unfortunate destruction of a valuable gem obligcelebrated as having produced some of the most ingly lent by them. In no instance did any valued precious stones in the world, have for symptom of phosphorescence appear; bat are some time past been unproductive, and are not markable increase in refraction was several now worked.—The diamond is pure crystallized times observed, and this appeared to be percarbon. Its hardness = 10, the highest number manent. The diamond possesses single or double of the scale; but the external coat is harder than refraction according to its different crystalline the internal portion, and may be rated at 10.5 or forms; and it has an extraordinary power of ra 11. The following are ascertained specific gravi- fracting light, the index of refraction being 2.44 ties of different varieties: Brazilian, 3.444; Bra- which led Sir Isaac Newton to suspect its inzilian yellow, 3.519; oriental, 3.521; oriental flammable composition. The dispersive quality green, 3.524; oriental blue, 3.525. The primitive of diamond is high; its index is equal to 0.0109. form of the crystal, and that into which the nu. Its refraction index (exceeded only by that of merous secondary forms may be converted by chromate of lead) equals 2.439; of some brown cleavage, is the regular octahedron, consisting of stones it has been observed to be 2.470, 2.487, 2 four-sided pyramids joined at their bases. The and 2.775.- Diamonds are found of various faces of the crystals are often rounded off, so as to colors, as well as colorless and perfectly trans present a convex surface, and the edges are also parent. The latter are most esteemed, and are often curved. The cleavage planes greatly facili- distinguished as diamonds of the first water tate the cutting of the diamond, and also present from their semblance to a drop of clear spring the most brilliant natural surfaces. Some dia- water. When of a rose tint and of clear water, monds found of a spherical figure are deficient in they are also highly valued. A yellow shade these planes, or they lie in a concentric arrange- is objectionable, as is a cinnamon color, a stone ment which renders their cutting

almost imprac- having these rarely being clear and sound. ticable by any known process. The diamond is Next to the rose, a green color is the least ob not acted upon by acids or alkalies, and when pro- jectionable; many very fine diamonds have this

« PředchozíPokračovat »