1392 



VEIN. 



haemorrhoids ; rupture ; disease of valves ; phle- 

 bolites ; calcareous degeneration ; fatty tumours ; 

 entozoa. 



Phlebitis. Phlebitis may be conveniently 

 divided into plastic and suppurative. They, 

 however, frequently exist together, are pro- 

 duced by the same cause, or give rise to each 

 other. 



Veins possess peculiar facilities for the pro- 

 duction of certain of their diseases, especially 

 inflammation of their lining membrane, caused 

 by the introduction of morbid materials into 

 their cavities ; which is a very general cause 

 of the disease now under consideration. 

 They are peculiarly subject to being opened, 

 on account of their superficial position, and 

 their being submitted to the surgical opera- 

 tion of venesection ; and it must be remem- 

 bered how large a superficies of the venous 

 cavity is exposed at every parturition to the 

 contact of those fluids which are secreted in the 

 healing of the placental wound. The veins si- 

 tuated in the osseous tissues present peculiar 

 facilities for the introduction of morbid mat- 

 ters into the circulation, on account of the 

 patency of their cut extremities, caused by the 

 adhesion of their walls to the unyielding tissue 

 in which they are embedded. Again, the di- 

 rection ofe th current of the circulation to- 

 wards the heart, is not likely to expel any 

 materials that are introduced into the vein, 

 but would rather tend to carry them on into 

 the mass of the circulating fluid. 



The absorbing function of veins is often re- 

 ferred to as a cause of the introduction of 

 morbid matters into the circulation, and this 

 especially as it regards pus, but it cannot be 

 strictly said that pus is absorbed in cases of 

 purulent phlebitis ; and I apprehend that the 

 distinction laid down by Hunter*, on this 

 point, is perfectly correct. It appears to me 

 impossible for any one acquainted with the 

 structure of the coats of blood-vessels, and 

 the anatomy of a pus-cell, to imagine that pus, 

 as such, can be introduced within a vein by 

 any process analogous to absorption. It is 

 true that pus may enter a vein bodily, and as 

 pus ; and it is equally true that pus may be 

 absorbed ; but the former is by introduction 

 through some lesion in the vessel's walls, and 

 in the latter the fluid is in some way altered be- 

 fore it can pass through the tunics of the vein, 

 if, indeed, a vein be here the agent of absorp- 

 tion. When pus is absorbed, as from a bubo, 

 or in empyema, it is attended with a different 

 series of symptoms and consequences from 

 those which arise when it is introduced bodily, 

 and pus is, in these cases, not to be found in 

 the veins ; and it must be remembered that all 

 the circumstances a wound secreting pus and 

 an open vein, or, what is tantamount to the 

 same, such inflammation of a vein as leads to 

 secretion of pus in its cavity, are uniformly 

 present where the characteristic results of 

 phlebitis occur. The same thing is imitated by 

 injecting pus into the veins with like results. 



Plastic phlebitis bears the same relation to 



* On the Blood, p. 360. 



suppurative, that the two forms of inflamma- 

 tion hold relatively to other organs. Plastic 

 phlebitis indicates a form of disease of milder 

 character, and consummated with results of 

 less seventy. Suppurative phlebitis is more 

 or less mixed up with the plastic form, and is 

 generally secondary to it. 



When a vein undergoes inflammation, the 

 affected portion throughout its entire thick- 

 ness becomes of a diffused red, which is not, 

 at this stage, to be distinguished from the red 

 stain produced by contact of the blood, ob- 

 servable, under certain circumstances, in both 

 arteries and veins ; this fades at the edges of 

 the inflamed portion. As the disease advances, 

 the part becomes irregularly mottled of all 

 shades, from purple to the natural colour of 

 the part ; with this appears, in the areolar tissue 

 of the veins, an effusion of sanious serum. The 

 effusion does not end in a serous exudation ; 

 but, as the disease progresses, a plastic effusion 

 is exhibited, not only in the tissue of the vein, 

 but also within its cavity. Whether or not 

 the previously developed serous effusion also 

 escapes in part upon the free surface of the 

 lining membrane of the vein, is not easily de- 

 termined, but in the stage now under con- 

 sideration it probably does so, as in other 

 serous inflammation. " At all events, at or im- 

 mediately after the time when such effusion 

 occurs, the tube of the vein becomes blocked 

 up with a coagulum of blood : this does not 

 occur at once, but progressively, beginning by 

 the deposition of fibrine upon the inflamed 

 surface, which deposition is increased by suc- 

 cessive layers, the original being for the most 

 part the most compact, until the entire tube is 

 blocked up. That part of this fibrinous product 

 is formed by the serous lining of the veins, 

 secreted from the vasa vasorum, is proved 

 beyond all question by the experiments of 

 Gendrin and Hope. Gendrin found that, by 

 securing a portion of a vein between two liga- 

 tures and removing all the blood it contained, 

 upon injecting some irritating substance into 

 it, plastic lymph was exuded in sufficient 

 quantity to fill the cavity of the insulated por- 

 tion.* In this experiment the fibrinous matter 

 was clearly true plastic lymph, in all respects 

 similar to the plastic effusion in other serous 

 cavities. Again, the experiments of Dr. Hope, 

 in which, by mechanical irritation, he pro- 

 duced warty excrescences on the valve of the 

 aorta, support the view I have taken. There 

 are many points in the formation of these 

 coagula in veins which are remarkable. That 

 they do, as already stated, consist both of 

 lymph-exudation and coagulated blood is more 

 than probable. But what determines the coagu- 

 lation of the blood in plastic phlebitis, is less 

 obvious. That the inherent power of coagu- 

 lation, which the blood in itself possesses, is 

 the cause, is not saying enough. There are 



* The experiments were originally performed 

 upon arteries, but were repeated upon veins with 

 similar results. Dr. Hope's were upon the aorta 

 near the heart : however, they prove the same fact 

 effusion of lymph on the lining of ^;he vascular 

 cavity. 



