irt 



OSSEIN. 



OSTRACISM. 



the nlt was oont-iined in 1000 of water; and while a Urge bulk uf 

 water entered tho osmometer, only a minute portion uf the alkaline aalt 

 escaped into the water of tin outr jar. Time, with a solution uf car- 

 bonate uf pytaah (1 put aalt to 1UOO water) in the ouuometer, the 

 lii|ui>l ruse in the stem 192 divisions in live hours, and for each grain 

 of carbuuate uf potash that wai diffused into the uuu-r cylinder morv 

 than 550 grain* of water entered the oamometer. Whim, how<\.r. .\ 

 solution containing 1 per cent of carbonate of potash waa used, only 

 63 grain* of water entered the ouuometer for each grain of carbonate that 

 passed into the outer cylinder. When the liquid rue* in the oaiuoineter 

 it ia termed poutire utmutc. 4. That dilute acid* and solutions of acid salts 

 produce a curnmt in the opposite direction, to that the column falls 

 in the ateui ; this ia known as ntyalire otmutt. Osmose ia remarkably 

 shown in salts which admit of division into a basic salt and a free acid. 

 Acetate of alumina, nitrate uf lead, chloride of zinc, and the salts of the 

 esquioxide* ! chromium and iron are good examples. In such cases 

 the acid diffuses outwards, and the inner surface uf the membrane 

 remains in a basic condition while the outer surface is acid condition* 

 which are highly favourable to rapid positive osmose. 6. That iu all 

 rsri of osmotic actions (except where alcohol and cane-sugar are con- 

 cerned) the material of the diaphragm is chemically acted on, and if 

 the diaphragm be made of a material not capable of decomposition by 

 the liquids, such as gypsum, unbaked clay, tanned leather, compressed 

 charcoal, although sufficiently porous, there is little or no osmotic 

 action. The most favourable cases are those in which the chemical 

 action on the diaphragm is different on the two sides both in degree 

 and kind, as when one surface is acid and the other alkaline. 6. That 

 two salts, when mixed, often exert an osmotic action very different 

 from what they exercise separately. Thus, sulphate of potash has a 

 feeble positive osmoee, but a very minute addition of carbonate of 

 potash increases its osmotic force fivefold, and a minute trace of hydro- 

 chloric acid arrests it. Chloride of sodium also reduces osmotic action 

 in other salts. 



The osmotic force must be distinguished from DIFFUSION ; for in 

 the latter case, if a saline solution were iu the interior reservoir, liquid 

 salt particle* would ooze through the membrane, and a certain quan- 

 tity of water would How back and take their place ; but if this were 

 a case of dill'usiuu the water would not be more than five or six 

 times the weight of the escaping salt, whereas the water entering the 

 osmometer may exceed the weight of the escaping salt 100 times or 

 more. Nor con osmoee be identified with capillarity. [CAPILLARY 

 ATTRACTION AD REPULSION ] Many of the saline solutions which 

 exhibit the greatest osmose are not distinguishable in capillary pheno- 

 mena from pure water. The force of the osmotic current may also be 

 measured in the following manner, devised by Liebig : Close the 

 open end of the short limb of a glass syphon by means of a piece of 

 bladder ; pour a little mercury into the bend of the tube, and till the 

 shorter limb with the saline liquid. Immerse the bend of the tube and 

 the membrane in water, leaving the extremity of the longer limb open ; 

 and as the water enters the tube the mercury will rise in the longer 

 limb, and when the column reaches a certain height the two liquid* 

 will intermingle without change of volume. The length of the column 

 which has been raised above the level of the surface of the mercury is to 

 be measured, and this, when compared with the lengths of the columns 

 obtained with other liquids, will give a comparative measure of the 

 osmotic force in each case. Thus it will be seen that chemical altinity 

 (shown by the action on the diaphragm) is converted into motive 

 power, capable of numerical expression. It seems most probable that 

 in the animal system there is an arrangement by which motive power 

 is obtained from the decomposition of the tissues. All parts of living 

 structure! are in a condition of incessant change, decomposition, ami 

 renewal. It may one day be demonstrated that the osmotic injection 

 of fluids is the associating link between muscular movement and 

 chemical decomposition. 



The flow of liquids through capillary tubes presents phenomena 

 closely connected with diffusion. They are well discussed in M. 

 Poiseuille's memoire ('Annales de Chimie,' 3 serie, xxi ). They are 

 also stated in a briefer form in Professor Miller's ' Elements of 

 Chemistry,' part i., 2nd edition, 1860, where the following remarks 

 occur : " Osmotic phenomena are constantly going on both in plants 

 and in animals ; for in their tissues liquids of very different natures, 

 sometimes acid, still more often alkaline, are circulating through 

 vessels necessarily constructed of flexible and porous materials, and in 

 the economy both of the vegetable and of the animal creation such 

 actions are of the highest importance to the due performance of the 

 vital functions. In fact, we as yet know not how intimately the entire 

 processes of absorption, nutrition, and secretion are connected \\itli 

 the o|-r,ition* of liquid diffunion and of endosmosis." 



KIN. A jx.culiar kind of gelatin found in bones, horns, Ac. It 

 is insolulile in cold water, dilute acids, alcohol, and ether ; but gradu- 

 ally soluble in boiling water, forming a jelly on cooling. 



OSSIFICATION is the formation of bone. This process occurs natu- 

 rally in the formation of the skeleton of man and the higher animal*. 

 [ BUXE, N AT. 1 1 IST. I > I v. J It also occurs in the reproduction of new bone 

 after Uie destruction or loss of old bones. [KiiACTURK ] Unification 

 occurs as an unnatural or morbid process. It is observed in several 

 tissues of the body. It is most frequent in the cartilages of the ribs, 

 in which it almost constantly occurs in advancing yean. In most 



persons bone begins to form iu these parts after the fiftieth year ; it 

 ..in. iinn- .- .nunt-nces between the ages of thirty and forty, but is 

 often delayed to a much later period ; and Harvey relates that in the 

 body of Thomas Parr, who died iu his 153rd year, the cartilages of the 

 ribs were sUll flexible and soft. The change is generally earlier in 

 men than iu women, and it affects the cartilage of the first rib sooner 

 than the rest. 



Next to the cartilages of the rib* those of the windpipe are most 

 liable to become osseous. Ossification of the cartilages of the ear, nose, 

 and KusUchian tube is, on the contrary, extremely rare, and in the 

 few cases in which it occurs it is not particularly connected with old 

 age. The cartilages of the movcable joint* never ossify. 



The tendinous tissue is that which, next to the cartilaginous, is 

 most subject to ossification. This change is not uncommon at the 

 insertion of the tendons of muscles that are much exerted, and in the 

 ligament of some fixed or scarcely moveable joints. Small piece* of 

 bone are also not (infrequently formed in the dura mater ; and these ' 

 are one of the sources of incurable epile|isy. Bone is also sometimes 

 formed in the fibrous coats of the spl.-i-n and liver. 



Ossification occasionally takes place in the false membranes produced 

 by acute inflammation of the pleura, and more rarely in those of the 

 pericardium ; and it is a common process in the adhesions whicl: 

 between the heads of bones exposed by ulceration of their cartilages, 

 producing the most fixed kind of anchylosis of the joints. 



A few remarkable cases are recorded of ossification of the muscles. 

 There is a skeleton in the museum of the College of Surgeons in 

 London, in which it has taken place to such an extent that nearly all 

 the bones must have been immovably fixed by the transformation of 

 the tissues by which, in the healthy state, they are moved. In equally 

 rare cases the crystalline lens, the vitreous humour, and some other 

 parts, are found converted into bone. 



In all these examples the material formed exactly resembles true 

 bone in its minute structure and chemical composition. In other 

 cases, as in ossification of the heart and arteries, the substance depo- 

 sited is composed of carbonate and phosphate of lime, as bone is, 

 but its particles have no definite arrangement. That which is calif. 1 

 ossification of the heart is not an affection of the proper substance of 

 that organ, but of its valves, in which earthy matter is son. 

 deposited, so as to render them stiff and unyielding, and destroy the 

 pliancy which is necessary for the performance of their functions. A 

 deposition of earthy matter in any part of the substance of tin 

 itself is very rare. [HEART, DISEASES OF.] 



The disease named ossification of the arteries consists in the ii- 

 tion of plates or rings of hard earthy substance iu their middle elastic 

 coats. This deposition is preceded by that of a peculiar soft or opaque 

 yellow substance, which becomes gradually hardened. The dep, 

 of this yellow substance iu the large arteries is so common that it is 

 very rare to meet with the body of an adult in whom it has not t..k. n 

 place to a greater or less extent ; and it not (infrequently commences 

 in early childhood. The change to earthy matter does not commonly 

 take place before the thirtieth year, and is very general after tin- 

 sixtieth. The roughness and irregularity in the circulation which it 

 produces in the large arteries and the ulceratiou of their lining nn-m- 

 branes which often accompanies it, frequently produce - 

 symptoms. The same changes are frequent in the arteries of the legs, 

 and the obstruction to the circulation which they produce generally 

 gives rise, if life is sufficiently prolonged, to the affection called 

 gaugncna senilis. [ ARTEHIKS, DISEASES OF.] 



OSTRACISM, the name for a singular institution existing for some 

 time among the Athenians. When any man became conspicuous by 

 wealth or by power, from whatever source derived, and was in conse- 

 quence thought likely to conceive plans of ambition dangerous to the 

 public peace and the stability of the existing form of government, thin 

 institution enabled the Athenian people to send him for a time into 

 exile, and thus rid themselves of the danger which they dreaded. It 

 was done as follows : When the occasion was thought to require it, a 

 day was fixed at an ordinary meeting of the Athenian people, for the 

 purpose of holding an ottracum. Un that day a part of tho market- 

 place (iyopd) was railed in, ten different approaches being left to the 

 part thus railed in. There was thus one approach for each of the ten 

 Athenian tribes. By these approaches the citizens, distributed accord- 

 ing to their tribes, entered the space within the rails, and there 

 deposited, in urns provided for the purpose, their shells or bits of 

 earthenware (ftffrpcuca, ottmea, whence the name ottracum), marked 

 with the name of the person whom they respect! v. ly thought it 

 desirable to banish. The nine arohons, together with the Proedri and 

 1'rytanes, superintended, seeing that everything was done projwrly, 

 and in the end counting the votes First of all they counted the gross 

 nnmlxT, which it waa necessary should be above six thousand, else 

 there was no valid ostracism. (Henmann, ' De Ontraci.-ni" Atliviiiense.') 

 If there were found to be six thousand votes, then they proceeded to 

 count th 1111111!* against different individuals; and the individual 

 against whom there was the greatest number of votes was sentenced to 

 ten years' banishment, or (changing the phrase) was attract**/. II,- 

 was then obliged to leave Athens within ten days after the sentence, 

 and unless a vote of the people recalled him before the expiration ,,i 

 that time, to stay in exile for ten years ; a period subsequently i 

 to five years. The goods of the ostracised person were not confiscated, 



