723 



SPIK1T OF SALT. 



SPLEEN, DISEASES OF THE. 



730 



tained and corrected : Let three pickets be driven into the ground in 

 a line and at equal distances from one another, and let the spirit-level 

 be set up successively in the middle between the first and second, and 

 between the second and third pickets ; then, having by the screws of 

 the instrument adjusted the spirit-tube so that the bubble of air may 

 retain the same place while the telescope is turned round on the 

 vertical axis, direct the object-end of the telescope successively to the 

 station-staves held up on the different pickets, read the several heights, 

 and take the differences between those on the first and second, and on 

 the second and third staff. Now the staves being at equal distances 

 from the instrument, it is obvious that any error which may have 

 existed in the line of collimation, or from the spirit-tube not being 

 parallel to that line, will be destroyed, and the differences between the 

 readings on the staves are the differences in the levels of the heads of 

 the pickets ; but unless the adjustments are perfect, this will not be 

 the case if the instrument be set up at any point which is unequally 

 distant from all the pickets; therefore from such point direct the 

 telescope to the staves, and take the differences of the readings as 

 before. On comparing these differences with the former, a want of 

 agreement will prove that the intersection of the wires is not in the 

 optical axis : and the error may be corrected by means of the screws 

 belonging to the wire plate. After the agreement has been obtained, 

 should the bubble of air not stand in the middle of the tube, it may be 

 brought to that position by the screw b, at one extremity of the case, 

 and the instrument is then completely adjusted. (Simms, ' Treatise 

 on Mathematical Instruments.') 



The spirit-level is usually provided with a clamp, y, and a screw, P, 

 by which when the axis of the telescope has by hand been brought 

 near the object, the coincidence may be accurately made by a slow and 

 steady motion about the vertical axis. 



The spirit-tube or level which is employed for the adjustment of 

 transit telescopes or astronomical circles is contained in a case with feet 

 or with loops at its extremities, in order that it may either rest above 

 or be suspended below the horizontal axis of the instrument to be 

 levelled ; also the upper part of the case is furnished with a graduated 

 scale, the divisions of which are numbered on each side of a zero point, 

 this point being usually placed near each of the two extremities of the 

 air-bubble when the tube is in a horizontal position. Having set up 

 or suspended the spirit-tube, the two particular graduations at which 

 the extremities of the air-bubble rest are marked ; and half the sum, 

 or half the difference of these numbers, according as the extremities 

 of thf bubble are in the same or in opposite directions from the two 

 zero-points, being taken, gives the distance of the centre of the bubble 

 from the middle between those points. The level being then reversed, 

 the graduations at which the air-bubble rests are again marked, and 

 half the sum or half the difference is taken as before. A mean of the 

 two distances thus found is the true distance of the centre of the 

 bubble from the middle point on the scale ; and the screw which 

 elevates or depresses one end of the axis of the telescope being then 

 turned, till either extremity of the bubble has moved, La a direction 

 contrary to that in which the centre of the bubble had moved from 

 the middle of the scale, through a number of divisions equal to that 

 mean distance, that axis will be brought to a horizontal position. This 

 method is used in preference to that of successive trials, in order 

 to avoid the trouble of making several reversions of the whole 

 instrument. 



The levelling-staff till lately in general use for finding the relative 

 heights of ground ia a rod consisting of two parts, each six feet long, 

 which, by being made to slide on one another, will indicate differences 

 of level nearly as great as twelve feet. The face of the rod is divided 

 into feet, inches, and tenths, or into feet with centesimal subdivisions ; 

 and a vane, or cross-piece of wood, perforated through the middle, is 

 moved up or down upon the rod by an assistant till a chamfered edge 

 at the perforation is seen by the observer at the spirit-level to coincide 

 with the horizontal wire in the telescope. The height from the ground 

 to the chamfered edge of the vane must be read by the assistant ; and 

 it being out of the power of the observer to detect any mistake in the 

 reading, it becomes very desirable that the graduations on the rod 

 should be sufficiently distinct to allow the heights to be read at the 

 spirit-level itself. The rod proposed by Mr. Gravat for this purpose is 

 divided into hundredths of a foot by stripes which are alternately 

 black and white, and are numbered at every foot in the usual way with 

 figures great enough to be seen on looking through the telescope ; the 

 tenths of a foot are indicated by lines longer than the others. A 

 imilar staff has been proposed by Mr. Sopwith and Mr. W. P. Barlow ; 

 and the former gentleman, besides the number of every foot, has given 

 a number to every first, third, fifth, and ninth decimal. Mr. Barlow's 

 rod is also divided into centesimals of a foot ; but the marks, instead 

 of being stripes whose edges are parallel to one another, have the form 

 of triangles : each tenth mark, however, is in the form of a lozenge, or 

 double triangle, for the sake of greater distinctness. 



SPIRIT OF SALT. [CHLORINE.! 



SPIhIT OF WINE. [ALCOHOL.] 



SPIRIT THERMOMETER. [THERMOMETER.] 



SPIRIT TRADE. [WINE AND SPIRIT TRADE.] 



SPIRITUAL COURTS. [ECCLESIASTICAL COURTS.] 



SPIROILIC ACID. Another name for hydride of nitrosalicyl. 

 [SAUCTLIC GROUP.} 



SPIUOILOUS ACID. Synonymous with hydride of salicyl. 

 [SALICYLIC GROUP.] 



SPIROUS ACID. Synonymous with hydride of salicyl. [SALI- 

 CYLIC GROUP.] 



SPLEEN, DISEASES OF THE. These do not appear to have 

 been much studied in this country, because they do not very frequently 

 occur ; they are, however, by no means of unusual occurrence in moist 

 climates, whether warm or temperate, as Italy, Holland, South America, 

 and some parts of India ; in fact, wherever malaria exists. The spleen 

 is liable to many sorts of disease : Dr. Bigsby (' Cyclop, of Pract. Med.') 

 enumerates as many as ten, but of these only the most important can 

 be here noticed. Splenitis, or inflammation of the spleen, may be 

 either acute or chronic ; though Dr. Baillie remarks that this organ is 

 much less subject to inflammation than many other of the abdominal 

 viscera. (' Posthumous Lectures and Observations on Medicine,' 1825, 

 unpublished.) Acute inflammation of the spleen, together with heat, 

 fulness, and tenderness in the splenic region, with pain upon pressure, 

 is accompanied with the usual pyrectic signs, and often with a pain 

 extending over the whole of the abdomen, but particularly in the left 

 side, and shooting from the diaphragm to the left shoulder. There is 

 also not unfrequently a dry short cough, and sense of constriction in 

 the pracordia, sickness, or nausea, and a discharge from the rectum of 

 black or livid blood, from a rupture of some of the splenic vessels. 

 Of this disease a remarkable instance, which terminated in nine days, 

 has been recorded by Dr. Ley, in the ' Transactions of the College of 

 Physicians of London ' (vol. v. p. 304). The texture of the spleen 

 after death was in this case so altered as to resemble an extremely soft 

 piece of sponge, of which the cells had been filled with an intimate 

 mixture of pus and grumous blood. On placing it iu water, innumer- 

 able vessels, as fine as the fibres of swans' down, floated separately, 

 rising from every point of the superficies of the organ. The contents 

 of this spongy mass having been removed by repeated washings, some- 

 thing like an attempt at the formation of cavities to contain the matter 

 manifested itself. No regular cyst however had been formed. All the 

 other viscera, abdominal and' thoracic, were healthy, except the uterus, 

 whose inner surface was gangrenous. The common causes of inflam- 

 mation of the spleen are much the same as those of inflammation of 

 the liver, namely, suddenly suppressed perspiration, especially from 

 currents of cold and damp air, and excess of spirituous potation ; 

 sometimes, however, the cause is too obscure for detection. With re- 

 spect to the treatment, the usual antiphlogistic remedies may be 

 employed, but promptly and energetically. Dr. Baillie says, he is not 

 aware that inflammation of the spleen would require a different treat- 

 ment from that of other viscera. 



If after a certain period the inflammation do not yield, it assumes 

 the chronic form, in which the variation in the severity and duration 

 of the complaint is very great. If it has accompanied ague, the symp- 

 toms may possibly not have been urgent in the outset, but it is almost 

 always a painful as well as formidable disease. It commonly lasts for 

 some months, and may continue for years with remissions. With 

 respect to the terminations of chronic splenitis, resolution does not 

 take place often ; suppuration is also rare upon the whole, and Dr. 

 Baillie says he " had never met with an abscess in the spleen in all the 

 dead bodies which he had examined." When pus is formed, it is of 

 the ordinary creamy kind, but is sometimes concrete ; it varies in 

 amount from a few ounces to many pounds. The matter may find its 

 way into the stomach, colon, or peritoneal cavity ; it may burst into 

 the left side of the chest, or into the lungs, inducing symptoms of 

 phthisis ; or it may empty itself outwards through the abdominal 

 walls. Ossification of the spleen after inflammation is rare, as is also 

 gangrene ; softening, induration, and hypertrophy, especially the last, 

 are much more common. With respect to the treatment of chronic 

 splenitis, perhaps the best plan that can be adopted is the combination 

 of aperients with iron and sedatives ; the good effects of mercury in 

 this disease being now generally considered precarious, trivial, and at 

 best temporary. Local applications, such as cupping, issues, setons, &c., 

 are sometimes productive of great benefit. 



Besides the inflammatory softening of the spleen, there is another of 

 a character quite peculiar, and unattended by any of the characteristics 

 of inflammation, wherein the structure of the spleen is more or less 

 destroyed, and it is often reduced to a simple bag, containing a sub- 

 stance which varies from the state of clotted or grumous blood to that 

 of tar. This was very frequent in the Walcheren fever, in which cases 

 the spleen was usually found after death of great size, and generally 

 a mere bag filled with a liquid like tar, and weighing from three to 

 five pounds. 



One of the most common diseases of the spleen is hypertrophy, the 

 most usual causes of which are ague and remittent fever. It is there- 

 fore chiefly to be found where these are endemical, but it is not very 

 uncommon in any part of Great Britain. The size which this organ 

 sometimes attains is enormous, and it is surprising to find how long 

 persons can carry about with them very enlarged spleens, and at last 

 die of some other disease. Dr. Bigsby quotes from Lieutaud the case 

 of a woman who had for seventeen years a spleen weighing thirty-two 

 pounds ; similar facts are to be found in Haller. Dr. Baillie mentions 

 (' Posthumous Lectures ' ) having met with cases where it was so large 

 as to occupy nearly all the left side of the abdomen, extending from 

 the diaphragm to the pelvis. When the enlargement is so considerable 



