No. 1241.

, JUNE 12, 1847.

A Course of LecturesON

THE PHYSICAL PHENOMENAOF

LIVING BODIES.

DELIVERED IN THE UNIVERSITY OF PISA.

BY PROFESSOR MATTEUCCI, F.R.S.

(Translated, for THE LANCET, by S. J. GOODFELLOW, M.D. Loud.,late Physician to the Cumberland Infirmary.)

LECTURE II.

Molecular A ttraction.-Capillary Attraction.-12nbibition.EVERY one knows that a living body can only continue toexist, by introducing new substances into its system. Thesesubstances, for the most part solid, are transformed andreduced to a liquid state, by means of certain functions ofthe organism; under this form, they penetrate into particularcavities, from which, after undergoing other transformations,they are afterwards expelled. We have seen, in the firstlecture, that the porosity of the tissues of living bodies allowsthem to be imbued and penetrated by the liquids with whichthey are in contact. We could not, then, give a satisfactoryaccount of the phenomena of absorption and exhalation,without regarding the influence of capillary attraction, im-bibition, and endosmose-phenomena which we already knowto be exercised by inorganic bodies.The importance of studying these two functions is so great,

that I intend to devote the whole of this lecture to the exa-mination of the purely physical phenomena of capillaryattraction and imbibition, in order to make you able to judgewhat part they play in the functions of absorption and ex-halation.To confine myself to a simple announcement of facts, I will

introduce here, under the form of propositions, the principalconclusions from the observation of capillary phenomena.

1st.—When a body is plunged into a liquid, the latter iseither depressed or elevated, and, according to the one or theother, it presents, at the point of contact with the solid, aconvex or a concave surface. In the first case, the body issaid to be wet, as when glass is immersed in water; and inthe second, it is not so, as when glass is placed in mercury.2nd.-When two bodies are placed in a liquid, the latter is

either raised or depressed between them, according as theyhave been moistened or not by the liquid, and it is necessary,for this, that the bodies should be so near to each other, asthat the two curved surfaces formed by the liquid shouldtouch. The elevation or depression of the liquid, above orbelow its level, is in an inverse ratio to the distance betweenthe two bodies.3rd.-If a glass tube, open at both ends, be plunged into a

liquid, the latter rises or falls, and this effect is the more con-siderable, the smaller the diameter of the tube. If the ele-vation or depression which takes place in a cylindrical tubebe compared with that between two slips of glass which areplaced at a distance from each other, equal to the diameter ofthe tube, it will be seen that the elevation or depression inthe tube is twice as great as that between the glasses. Theliquid rises and adheres to the glass, or wets it; on the con-trary, it is depressed in the tube, if the liquid is not capableof wetting it. In a tube of one millimetre* in diameter,water rises thirty millimetres, mercury is depressed thirteenmillimetres.

It will readily be admitted, that capillary action mustexercise great influence upon the functions of animal andvegetable tissues, if we reflect that the vacuities, the inter-stices, and capillary tubes of these tissues, are from 1/100to 1/200 of a millimetre in diameter.4th.-The concave surface of the raised liquid, and the con-

vexity of that which has been depressed, belong to an hemi-sphere, the diameter of which will be equal to that of thetube.5th.-A drop of water introduced into a conical tube of

glass, plainly resorts to its narrowest portion; a drop of mer-cury, on the contrary, is carried to its largest part.6th.-The phenomena which have engaged our attention

are entirely independent of the volume of the solid body which

- - * A millimetre is one-twenty-sixth of an English inch.

is plunged into the liquid, consequently the thickness of thewalls of the capillary tube exercises no influence upon theiraction.

7th.—These phenomena take place freely also in air atordinary pressure or when condensed or rarefied, in vacuo,and in any gas that we may select.8th.-All bodies, of whatever nature, if they are capable of

being moistened, furnish the same results.9th.-For with the same liquid, and in the same tube, the

elevation or depression of the column diminishes according tothe temperature of the liquid.10th.-The elevations and depressions are independent of

the density of the liquid. Thus, if we represent by 100 theelevation of water in a tube, that of alcohol will be 40, that ofthe essence of lavender, 37, and that of a saturated solution ofsea salt, 88.llth.-Two bodies floating upon a liquid within a certain

distance, are attracted towards each other, and unite, providedthat both are capable of being moistened, or that both are notso. They appear to be repelled if only one be moistened. Itis according to this principle that we explain the tendency oflight bodies, which float on water, to be attracted towards thewalls of the vessels which contain them.

12th.—Whatever be the height to which a liquid is raised,it never escapes at the upper aperture of the capillary tube.This is a necessary consequence of the result, which we havealready stated. In fact, it will be sufficient to reflect that thesurface of the liquid column in the tube is always concave, andthis is why, if we add sufficient water in one of the arms of acapillary tube bent upon itself to make the surface of thecolumn at first horizontal, and then convex, we find the sur-face of the liquid column in the other arm remaining alwaysconcave, and at a level more elevated than the first. When-ever the surface becomes convex, the force of capillary depres-sion is exerted. You must not believe that the water whichflows from a wick of cotton, saturated with this liquid, one endof which is held downwards, is occasioned by capillarity,because it is only necessary to suspend it horizontally, andthe escape ceases.

I cannot enlarge upon these phenomena so as to give thetheory, which falls entirely within the sphere of the highestmathematical analysis. The results of the observations whichI have already cited are sufficient to prove that these pheno-mena depend upon that force which we term molecular attrac-tion, or the force which is exerted among molecules, andceases to act as soon as they are separated by the smallest dis-tances.To avoid all false application of capillary phenomena to the

animal economy, we must not forget that a space completelyfilled with liquid is incapable of exerting any capillary ac-tion ; that the action of a tube upon liquid is owing, less to thematerial of which the tube is composed than to the nature ofthe liquid with which its internal surface is moistened; andlastly, that it is never by the agency of capillary action thatliquids escape at the superior opening of the tubes in whichthey are raised.The phenomena of imbibition, of hygroscopicity, &c., are

generally of the same nature as the preceding, and theydepend upon the same force. A piece of sugar, a cottonwick, a tube of sand, cinders, or saw-dust, placed in con-

tact with water, or with any other liquid which wetsthem, quickly draws the liquid through all their mass-that is to say, becomes saturated with them. This isalso the case with certain tissues, cartilages, and tendons,which, if dried, and then plunged into water, regain, in ashort time, all the properties which they possessed duringlife. This effect is produced by the water which they ab-sorb. The same thing happens in the remarkable instanceof the rotiferous animalcule, which is restored to life andmotion when placed in contact with a drop of water. Thesephenomena of imbibition are also observed in the filtration ofliquids. When a liquid holds in suspension some solidparticles, we see them separate from. it, and rest upon thefilter, while the liquid soaks into its substance. When adrop of chocolate, or ink, falls upon cloth or filtering paper,it produces a dark spot, surrounded by a zone less deeplycoloured. The same effect is observed when the blood is

diffused in the cellular tissue under the skin; the serum iscarried to the margin of the stain, and separated from thecolouring matter.Among the phenomena of imbibition, we must first con-

sider the force of adhesion between the liquid and the sur-faces of the solid particles, afterwards the action of capillarity,properly so called, seeing that in sugar, or a mass of sand or

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ashes, and in organized tissues, there certainly exist ex-

tremely minute cavities, which ramify in their interior moreor less tortuously.The phenomena of imbibition merit a more attentive study

than they have hitherto received. I will give you the resultsof some experiments which I have made upon this subjectwith Professor Cima. I should have wished to do it at

greater length. Some glass tubes, about two centimetres(about four-fiftlis of an English inch) in diameter, were filledwith white sand, which had been passed through a very finesieve. The extremity, which was plunged in water, wasclosed by a piece of cloth tied round the tube. The precau-tion was first taken of drying the sand by means of a water-bath, and then introducing it by the upper part of the tube,taking care not to shake it when full, in order that the massof sand should not be unequally compressed. Six tubes thusprepared were plunged at the same time into six differentliquids, of the temperature of 12° centigrade, (730 Fahr.)The action of imbibition continued to raise the liquids inthe tubes for ten hours; it was rapid at first, but alwaysproceeded more slowly, according as it approached the limitsat which it ceased. Each tube was plunged about halfa centimetre (quarter of an English inch) in the liquid, andcare was taken to replace the fluid occasionally, so as topreserve a uniform depth in each vessel.

Subjoined is a table, showing the highest elevation attainedby the different fluids. All the saline solutions were of thesame density—10° of the aerometer of Baumé.

This table shows how imbibition takes place in differentdegrees in various liquids. In thick solutions of gum, inboiled starch, or in oil, there is scarcely any imbibition. Itis also very small in concentrated saline solutions, and in allthose liquids which hold in suspension very minute solid par-ticles. In the last case, imbibition produced a kind of filtra-tion. This phenomenon of imbibition in solutions which con-tain very small solid molecules, suspended in the liquids, maybe of great value for the purpose of appreciating the differentproperties of blood according to its density. In certainmaladies, its density and viscidity are much diminished; andin these cases, serous infiltrations take place, such as areobserved by the same causes from great losses of blood.We shall presently find that alcohol, ether, water, and

aqueous solutions, introduced into the stomach of livinganimals, disappear, but after diiferent intervals of time; oilremains there a very long period.

It will, perhaps, be of some importance to compare alcoholat 360 Baume, and distilled water, by means of tubes filledwith sand, pounded glass, and sawdust. Witness the eleva-tions that I have obtained :-

Tube with sand. Tube of pounded glass. Tube filled with sawdust.

Alcohol, 85mm. 175mm. 125mm.Water, 175mm. 182mm. 60mm.

In examining these results, it is very evident that thealcohol is raised less than the water in the sand and in thepowdered glass. This agrees with what took place in thecapillary tubes. ,.

I also plunged into water two tubes, the first of which con-tained double as much pounded glass as the second, with thefollowing results:-

In the first tube, the water was raised 170mm.; in the

second, 107mm. It is not easy to give an explanation of therelative heights in the two tubes; and yet it is natural thatthe water should rise higher in the tube which contained thedouble quantity, if we reflect upon the greater extent of solidsurface for attracting the water, and to the much smallerdiameter of the capillary cavities.

This phenomenon of imbibition is constantly witnessed, andunder a great number of circumstances, in animal and vege-table tissues. These, being abundantly furnished with minutespaces and capillary tubes, very readily imbibe and absorb thesolutions with which they are in contact. This is what takesplace in the cellular tissue, and in the parenchyma of thelungs: the opposite effect is observed in the epidermis.

I have also made it a subject of investigation, whether anydifference in the phenomena of imbibition is produced bytemperature. Two tubes prepared with sand were equallyplunged in water: the temperature of one was 55° cent., ofthe other, 15° cent. The results obtained were as follows:-

The influence of temperature upon the degree of imbibitionis, it will be seen, very considerable. It is also known, thatin animals, absorption, either by the skin, or in the internalstructures, is more active in proportion to the heat of thesolution.

I am convinced that imbibition goes on with equal intensitywhen the surrounding air is saturated with moisture, and whenit is dry. Another result, no less remarkable, is observed,that the imbibition of sand, ashes, and sawdust, goes on aswell under the exhausted receiver of an air-pump as in theopen air. No difference was perceived in the height of acolumn of water at the end of ten minutes; the only peculiarityobserved was, that imbibition proceeded more rapidly m vacuothan in air in the first few seconds.

It may be asked, whether by the action of imbibition aliquid may rise to any height. It would appear, at first sight,that a column of sand, ashes, or any other powder, plunged atone end into a liquid, the level of which was always main-tained, would carry the liquid to any height by the force ofimbibition, till the whole column were saturated. In fact, ifwe consider separately the action of each of the layers whichform the column, we may conceive that after the imbibitionof the first layer in contact with the liquid, the particles ofthe layer immediately above it will take from the first partof its water, and that the first will again take from the fluidmass as much as it has lost. By repeating this reasoning forall the successive layers of the column, we may conclude thateach of them takes the same quantity of fluid as if it actedalone; and thus, if we suppose the level of the water constant,the column, however long it be, ought to be entirely saturated.But experience does not confirm this reasoning: the fluidrises rapidly at first-then the motion slackens-and aftergaining a certain elevation, it stops. This effect cannot beattributed to the evaporation which takes place in the higherlayers of the column; for water rises in a column of sand toexactly the same height in an atmosphere saturated withaqueous vapour as in dry air. I am not able to accountfor this limit of imbibition, except by admitting the existenceof little canals reaching along the whole length of the columnof powder; and, in consequence, capillary action will intervene,as well as the adhesion of the liquidto the surface of the grainof sand.*

It is impossible not to perceive that imbibition plays agreat part in the movement of the juices of plants, and in thephenomena of the capillary circulation of the blood of animals.In another lecture, we shall see that living plants and animalshaving some one part plunged into a saline solution, the pre-sence of which is easily recognised by means of re-agents, arequickly penetrated by it throughout. It will be sufficientfor me to mention the experiments of Hales, and those morerecently made by Boucherie; the latter has seen a poplar,ninety-two feet high, absorb by the trunk, in six days, theenormous quantity of sixty-six imperial gallons of a solution ofpyro-lignite of iron.

I will here relate the experiments made by Hales, tomeasure what he calls the force of aspiration of powderedbodies, and stems of trees-phenomena in which imbibi-tion plays an important part. This experimenter furnishedhimself with a large tube of glass, closed at the upper end,and filled with ashes or with minium, reduced to a fine’; powder. A cork was fitted in the open end, in the middle ofwhich a narrow tube of glass was fixed, three or four feet in

length. This second tube was filled with water, and quicklyinverted over mercury. The mercury soon rose, and gainedan elevation of several inches. In one experiment, Hales sawit rise seven inches, which is equal to a column of water ofeight feet.

If the tube, full of ashes, is replaced by the stems of a tree,or, better still, if the branch of a tree is tied to a glass tube,filled with water, and inverted over mercury, the latter willrise, as in the preceding experiments with the powders.Hales regarded this phenomenon as depending upon a forcewhich he called the force of aspiration.

* Might not the force of gravity of the imbibed fluid counterbalance, inthis case, that of imbibition ?-TRANSLATOR.

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Here are some experiments which explain these facts in asimple and satisfactory manner. It is easy to show that theascent of the mercury equally takes place in two tubes pre-pared like those of Hales, but yet differing from them, inhaving one tube filled with ashes, open at the top, and theother closed. And yet it must be observed, that this resultwill not be obtained if the column of ashes be short, or if thiswere less filled. I have also made the following observationswith a similar apparatus to that observed by Hales. I fluted atube of lead with clay, to that of glass containing the powder;by means of this I could easily extract the air which was.above the ashes. At the moment when the column of mer-cury began to rise, I made a vacuum, and not only did the ’,mercury not go down, but it even continued to rise. It is,then, indubitable, that the ashes form a partition above thecolumn of water, which exactly performs the office of theclosed tube. In fact, Hale’s apparatus is a barometer. In.another experiment, at the moment when the mercury rose, Icovered the whole with the receiver, and made a vacuum; atthat instant the mercury fell again entirely. I have wit-nessed the same phenomena, by substituting, for the tube filledwith ashes, a stem of a tree, having leaves attached to it. IfI introduce the superior part of this stem into a ball fromwhich I have withdrawn the air, the mercury continues to.rise; but, on the contrary, it immediately falls again if I forma vacuum on the vessel containing the mercury. We mustconclude from this, that that which Hales called theforce of aspiration, is merely the action of a barometer;that whether the column of ashes, or the leaves and trunkof a tree, form the upper closed part of a barometer, thewater penetrates the ashes or the vegetable tissue, by im-bibition, and the atmospheric pressure gradually forces upthe liquid.We must, however, remark a very curious fact which takes

place when we use the branch of the tree, as in all the otherexperiments of Hales, that the column of water continues toascend, which would lead to the conclusion, that the vapour ofwater is exhaled by the leaves without these ceasing to.act as the closed tube of a barometer. It would appearthat Magnus obtained the same result in closing by a mem-brane the upper part of the tube; and as already stated,the water continued to ascend; but it is probable thatthe phenomenon becomes, after a little time, less manifest,and ultimately ceases, in consequence of the disorganiza-tion which takes place as well in the membranes as in theleaves.

I will not leave this subject without relating some experi-ments made for the purpose of producing, by the simple playof the capillary forces, and of molecular attraction, the effectsof chemical affinity. If we reflect, that a liquid, of whateverkind it be, is constantly raised to the same height in a capil-lary tube; that during the imbibition there is more or lessevolution of heat, as the experiments of Pouillet prove; andwhat is more, that there is, according to Becquerel, a disen-gagement of electricity; and lastly, that capillary attraction isonly exerted at very limited distances, and between the mole-cules of bodies,—we must admit that this force combines theprincipal characters of chemical affinity. We know thebeautiful remark of Dobeirheiner,that when a mixture of waterand alcohol is enclosed in a vessel, and exposed to the air,the water alone escapes. In this case the water is imbibedby the membrane more readily than the alcohol, and is dis-sipated by evaporation. Another fact, more conclusive, isthat mentioned by Bergelius, that salt water, in its transitthrough a long tube of sand, flows away, more or less com-pletely deprived of its salt. I have confirmed this experimentby means of a tube filled with sand, of about eight metres(twenty-six feet) in length, and I found that the density ofthe water, introduced at the superior orifice of the tube, wasto that of the liquid flowing from it as 1 : 0.91; but I shouldadd, that this difference of density is not constantly in thisproportion, for after a certain time the saline solutionis as dense at its exit from the tube as it was whenintroduced ; which proves that the decomposition of thesolution takes place during the first action of contact be-tween it and the particles of sand. I obtained an oppositeresult by employing a solution of carbonate of soda, whichI passed through a similar tube of three metres (ten feet)in length. The density of the liquid, after having traversedthe layers of sand, was to that before its transit as

1,005 :1.These phenomena are very important, from their extensive

application to some of the functions of living bodies, whichcannot be entirely explained by the influence of capillarityand molecular attraction.

Hospital Reports.ST. BARTHOLOMEW’S HOSPITAL.

MEDICAL REPORTS FROM THIS HOSPITAL.

By E. L. ORMEROD, M.B. Cambridge,MEMBER OF THE ROYAL COLLEGE OF PHYSICIANS ; DEMONSTRATOR OF

MORBID ANATOMY AT ST. BARTHOLOMEW’S HOSPITAL.

IT is proposed, in the few following papers, to illustrate thevarious affections of the respiratory organs, which most coni-monly present themselves in the wards of St. Bartholomew’sHospital.Croup is, beyond all others, the disease of the respiratory

organs that is most rarely met with in this hospital, so rare,that none but doubtful cases could be brought forwards inillustration of it. Acute laryngitis is more common; as theresult of accident among children, it is not uncommon inthe surgical wards; and an instance of it, in the idiopathicform, in an adult, was supplied in Case 56 of these reports.The following case affords another example of the samedisease :-

ACUTE LARYNGITIS; TRACHEOTOMY; SUCCESSFUL TERMINATIONOF THE CASE.

CASE 57.—Eliza W-, aged twenty-one; admitted March31st, 1847; Hope back ward. Thin, slightly made; faceanxious, livid; skin cool; pulse 120, small, soft; bowels con-fined ; tongue moist; sits up in bed, breathing with difficulty,(48,) with a loud hissing noise, scarcely able to speak, thesupra-clavicular spaces forming deep hollows, on inspiration,and any attempt to swallow producing the most agonizingdyspnoaa. This has been the case for two days.

History.—Married; delicate; the catamenia regular; had asimilar attack six years ago, which was successfully treatedby leeches. She is liable to cough, but has never hadhaemoptysis. Ten days ago, she had an ordinary cold, withhoarseness, and having been shortly afterwards much alarmedby one of her acquaintance having been murdered, she attri-butes the present symptoms to that fright. Her symptomshave been gradually getting worse; for five days they havebeen very severe, but for the last two they have been extreme,and she has had no sleep.On A uscultation, good but feeble respiratory murmur is

audible beneath the clavicles, with good resonance on per-cussion ; behind, respiration is feeble and sibilant, with here,also, good resonance on percussion; the fauces appear quitenatural, neither swelled nor discoloured; pressure on thelarynx gives great pain. She had just taken a large dose ofpurgative medicine; she was ordered to have twelve leechesapplied to the larynx. -Half-past three P.M.: The leecheshave given some relief; face paler, less dusky; breathing ashurried, but not as laboured, as before; she swallows a littlemore easily, but her agony is extreme when she swallowsmore than a sip at once, or whenever she coughs; she is evi-dently much weaker than she was at noon.

It was not thought safe to leave her. The trachea wasopened by Mr. Skey, just below the cricoid cartilage; verylittle haemorrhage took place; she coughed a good deal on thefirst introduction of the canula; and expectorated much toughmucus through it; her breathing was immediately much re-lieved by the operation. Ordered to have a blister plasterapplied to the chest, to take fifteen minims of ipecacuanhawine, with one drachm of mucilage, out of half an ounce ofdistilled water, every other hour, and some linctus, to quiether cough.Eight A.M.—Has had half an hour’s comfortable sleep since

the operation; breathes easily through the canula, (36 to 40;)pulse 132, small and soft; three loose evacuations from thebowels, the last of a light-green colour.

April 1st.—Slept well during the night; face composed;respirations 30, easy; the supra-clavicular spaces being nolonger depressed; pulse 120, small, without much power;bowels not open since yesterday evening, but she has a gooddeal of tenesmus; she has a little cough, with very free muco-purulent expectoration. The blister drew pretty well.Ordered, a saline draught with antimony, thrice a day.2nd.-Good sleep through the night, by periods of about

two hours, with equally long intervals: she swallows easily,though her mouth be so full that the fluid is running out atthe corners; expectoration is quite free, the mucus looser.Ordered to continue.3rd.-At six P.M. yesterday her breathing became oppressed;

she had tickling and pain in the throat, which was onlypartially relieved by the canula being cleaned. At ten r.at.,