Annee 1736) communicated some ob- servations and conclusions upon the subject matter of the fore- going essays of M. Heconcluded, " That whenan arterj-is divided, a coagulum does not alwaj'sform; thatthe retraction of the arterj- has not. Hethoughtthat hemorrhageisalwaj^s permanently preventedby thechanges which take place in the surrounding cellular tissue, and by adhesive inflammation of the' arterial walls themselves.
Rokitansky (Pathologische Anatomic, 1856) regarded the walls of the vessel as the origin of the material whichfinally fillsthelumen and becomes organized.
REPARATORY
Woclienschrift, 18G4) made a series of experimentsupon dogs and rabbits, directed to thedetermination of the mode of vascularization of thethrombus. That by theend of thethird or fourth week, the vessels of thethrombus have formed a union withthose of the adven-. The author states that—the tiirombus never organizes; the muscle-fibres of the media arenever concerned.
Hethinks thathis preparationsclearlydemonstrate that inthecase of the single ligature the organizing elements of the permanent clotarederived from the tunica intima.
SUMMARY OF PREVALENT OPINIONS
Pitres (Recherches experimentales surle modedeforma- tion etsurlastructuredescaillotsquidetermincntI'hemostasie.. usually spontaneously secured by a clot composed of three distinct portions: an external part, which is a simple blood coagulum, and which is only an accessor}'; a middle i)art,.
INFLAMMATION ARTERIES. 17 cerning the organization of tlie blood, there has at no time
The thrombus doesnot remain in the samecon- dition for all future time, but it becomes transformed into cicatricial tissue, shrinks and atrophies,when thearterj'- at the point of division has become solid bythecomplete fusion of this cicatricial mass with the walls of the vessel. In what these changes of the blood-clot actually' consist, the microscope gives valuable evidence. The clot ishomogeneous throughout, thatis to say, there is no stratification or group- ingof the blood-disks, either of the white or red; but, on the contrary, they are scattered evenly through the entirecoagu- lum.
It is thefurther development ofthe colorless cellsofthisclot which secures the definite termination of the ivhole pi'ocess.
INFLAMMATION
It is thus thattheirideas concern- ingtlienature of theinflammatory process in wounded arteries are made to coincide entirelywith and to give some further support to Cohnheim's theory of inflammationin general.
PERSONAL OBSERVATIONS
Theywere intended to supply a full series for the satisfactory study of the process of healingafteracupressure. This clot wasusually egg-shape, and it did not fill theentire calibre of the vessel. The bottom of the blood-clot was adherent to the bottom of this cup-shape cushionof colorless cells,and it was also adherent toone of itssides.
In conse- quence of being viewed in profile,many of the cellsappear to bespindle-shape. In . still greaternumberare tobe seen round orpolygonal granular cellstwiceand eventhree times thesize of the latter. The cells of the plastic clot presented changes which were a progression of thosealready noted in thetwo youngerclots.
The cellular infiltration of some of the tissues in the neighborhood of the ligature was verydecided. As has been alreadyremarked, each of the lowerportions aiJi)ears to have been similarly constituted. Whatis thesignificance ofthis interesting serpentine lamel- lation of each of those three lowerportions of the blood-clot?.
Soon, however, this portion of the vessel began to dilate, reaching finally to nearlytwice its original diameter. Oval-andlozenge-shape cells of the plastic portion of thethrombus,their outlines,processes,and nucleibeingwell seen.
REPARATORY INFLAMMATION
The sur- face of the granulation is covered with one or two layers of epithelioid cells; not the slightest sign of a capillary loop occupying the axisof the granulation, northeIsast trace of a vessel to be seenanywhere in the inner layers of the media, preparingto send a vascular loop through the elasticlayer of the intima. The blood which permeatedthe plastic clot travelledby wa}- of the previously mentioned capillaries and blood-channels, and was supplied from the open artery above thethrombus. Preparations from thrombi fifteen days old exhibited only a morecompletedevelopment of the conditionsshown to bepres- entin the last-discussed stage of organization.
I wall merely addthat theblood coagulum,whenliftedup fromitsproper bed bythe growth of the plastic clot, still remained, at tliis date, as at first formed. No changes other than those of the inevi- table consequences of contraction of the fibrin were to be re-. The clotswere attached to thetop of the organized or plastic clot only by their base.
When, on the otherhand, the blood-clot had remained in its primitiveposition, firmly attached to the w^alls of the arter}-, the previousl^^mentioned granulations had so increased innumber and size as tocause, probably by pressure, a progressive degeneration of the red blooddisks, andtheir slow disappearance bygranulardisinte- gration and absorption. Preparations for the establishment of an anastomosis between the vessels of the clotand those of the wallswere now for the first time definitely observed.
IXFLAMMATIOX IN 39 would occasionall}' be seen extending toward the intima, but
Vascularized granulation-tissue,thedark lines in whichrepre- sent bloodvesselswhichare seento bein communicationabove withthe open lumen (L) of the artery, v. The two varices communicate by means of smallcapillaries passingbetween breaks in tlie elas- tic laj'er (e) of the intima. i. A few smaller vessels jjass directly from the varices to the capillaries at the sides of the plastic formation obstructing thelumen, p.
It is observable, both in this figure and in the one imme- .. diately preceding, that there is a rich capillaryplexus extend- ing from the bottom to the top of the plastic clot, d, d', is . a blood-clot showing the serpentine lamellation and exhibit- ing no sign of approaching organization or degeneration. At the sametime they demonstratedthefactthat thesedouble blood-coagulawere similarinconstitution tothose stratified clotsfound aftertheusual application of the ligature. Thecells ofwhich thelatter consisted were in the main similar to leucocytes, which had probably wandered in through the laceration in the coats produced by the ligature.
The lowerblood-clot appeared \ery com- pletely tofill out that portion of the calibre of the artery in. The most striking phenomena were ob- served atthelevel of the point of compression bythe forceps. Atthis point there were very decided indications of a lively state of activity in the intima and innermost layers of the media.
This cellular infiltration of the inner layers of the media waslimited to the innerlamellae, and was not even here decided. Tliere was no decided increaseof protoplasmicelements, either in the exter- nal layers of the media, or in the adventitia.
REPARATOKY INFLAMMATION IN ARTERIES. 43 pressure had been applied, had met and formed an extensive
On a level with B the enormously thickened intima, p', and thegrowing inner layers of the media are more or less blended. The structure of the granulations themselvesis cellular, in fact identical with those granulations which form the plastic clot after the ordinary ligature, v. Capillary vesselsand smallblood canals in the inner la^'er of the media and the thickened intima: theyare in communica-.
An exmnination of the few made has led to the conviction that the process of healingafter aeu-. Respecting the lengthof time required forthe perfect estab- lishment of the collateral circulation, the following observation ma}' havesome significance. Tschausoff has repeated the experiments of Bubnotf, and has declared that he has been unable to confirm the observations of the latter.
We are,then, forced to the conclusion thatif any leucocytes atall have wandered into the clot, the}'could only have come fromtheblood in the lumen of the artery above the throml)us. 50 THE TONER LECTURES. which may, by way of the blood current, have travelled to thethrombus from some distance. At tlie commencement of the observation, this cell (6) was flatly ai)plied tothe capillary wall as theother endothelial cells now.
During an energetic increase in the velocity of the current this was actually observed to take place. Nowprecisely this is found tobe true respecting the blood in the inflamed stumpof a ligated artery; on the other hand, ithas not yetbeen observed of the bloodin more general inflammations.
REPAEATORY
54 THE TONER LECTURES
C OX CLU SIGNS
The rapidity of the healing process is usually propor- tionate to the growth of the plastic clot. The pres- ence of the latter is notessential,for theformation and organi- zationof theplastic clot occasionally take place withoutit. Some days before any trace of a vascularcommunication between the plastic clotand thevasa vasorumcan be discovered, the former is thoroughly permeated by a rich capillarynetwork which is in communica- . tion with the open lumen above the thrombus, by means of blood channels or sinuses of considerable size located mostly in the superior portion of the plasticclot.
Usually betweenthefiHteenthandthethirtiethdayafter ligation an anastomosis is established between the vessels of the clot and those of the walls of the artery. The communica- . tion is established at the bottom of the arterial stump where the intima and media have been cut through by the ligature. At this date theelastic layer of the intima,fromthetop nearly to thebottomof theclot, is sharply defined, presents little evi- .. dence of softening, and offers no perforation for theestablish- .. ment of a lateral anastomosis between the vasavasorum and the vessels of theclot directlythrough thesides of theartery-.
Theplastic clot, b}' agradualmetamorphosis into cica- tricialtissue, and by a subsequent cavernous transformation of the latter, finallydisappears—the only remains of the vessel and of the clotbeing a tough fibrous cord. If theblood-clot,duringthe firstdaysofitsformation, become firmly adherent to the vessel-wall, the increase in the size of the plastic clotcauses granulations springing from itto .. grow into the crevices and channels of the blood coao-ulum. Through the continued invasion of the blood-clot by these granulations, and their increase in thickness, the blood-clot disintegrates in consequence of the gradually increasing pres- sure,andis finally absorbed.
If,inaddition to the usual method ofapplying a liga- ture,compression'be produced upon the walls of the arter}^ a short distance above the point ofligation, in such amanner as to slightly rubtogether opposite points of the surface of the internal limitingmembranewitlrout rupturingthelatter,andto excite at that place anirritation, the plastic clot mainly forms at that point instead of at thelevel of theligature, and the obliteration of the lumen of the vessel and the permanent arrest of hemorrhage are more rapidl}- and more certainly se- cured. A practical application of the same procedureto the usual methods ofperforming acupressure may, aprio7-i, beex- pected to secure similarly good results.
REPARATORY INFLAMMATION IN ARTERIES. 57 consequence of the slowness of the healing process present in
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