capillary coats, and effusion of lymph, etc., into the surrounding cellular interstices took place.

And if we carry the parallel further between the phenomena of capillary and of venous inflammation as I have now sketched it, we may recognise a strong similarity, if not a perfect identity, between their respective causes and modes of origin. For, whilst we have traced the origin of phlebitis, in the great majority of instances, to an altered condition of the vitality of the lining membrane of the veins on the one hand, and an abnormal condition of the blood on the other, do we not see that it is essentially to the same conditions we may trace the origin of capillary inflammation in the great majority of cases? Thus, in the various injuries inflicted upon the capillaries of frogs in the prosecution of microscopical observations, as well as in the various forms of injury from mechanical violence received into the surgical wards of hospitals, do we not observe but the operation of causes all tending to one given effect, viz., the injury or impairment of the vital power of the vessels of the injured parts? whilst, in the operation of all septic agencies, abnormal diathetic conditions, febrile movements, and constitutional disorders, do we not equally recognise the presence of a widely spread and dissimilar class of causes, having all a common tendency to a common consequence, viz., a disordered or abnormal condition of the blood? And just as it happens that in the one case we see extensive tracts of the capillary system obstructed and inflamed from constitutional causes alone, without any direct injury or violence being applied to them, so do we see, in the other, extensive tracts of the venous system obstructed and inflamed from constitutional causes alone, irrespectively of any direct injury of these vessels, or of the direct insertion of any vitiating matter into them calculated to excite it.

But we may yet carry the parallel a step further, and show that the same general laws which govern the selection of particular tracts of the capillary system for the seat of inflammation from systemic causes, equally govern the selection of particular portions of the venous system in regard to inflammation under the same circumstances. For, just as we know that previous injury, relative weakness, or antecedent disease, renders particular organs throughout life predisposed to inflammatory action from constitutional causes, so in the case of the veins, it is the fact that it is those portions of the venous system which are relatively weak, or have sustained antecedent injury or disease, that are the most predisposed to inflammation in connection with the same causes. Thus it may be said that the utero-placental veins are predisposed to it by being torn across in the removal of the placenta; that the crural veins of parturient women are generally predisposed by the actions of pregnancy and the pressure of the gravid uterus; and that any vein surgically or otherwise wounded or injured, becomes thereby predisposed to inflammation. One other circumstance only need be referred to, which is the influence of cold partially applied to the body in predisposing veins to morbid action. This is true generally in regard to the capillaries, and experience teaches that it is equally so in regard to the veins.

General Application of the foregoing Inquiry. And now, gentlemen, in conclusion, let me briefly recapitulate what appears to be the great practical lesson or corollary to be drawn from the whole of the investigation I have laid before you. It appears to me to be plain and unmistakeable, and to define clearly the true relations of phlebitis to the phenomena of phlegmasia dolens. We learn from one series of observations detailed, that phlebitis may be produced and occur in a local or isolated form as the result of a local cause, as shown in the instance in which the crural veins were inflamed from the femoral to the cava by the application of a chemical irritant; and here all the genuine phenomena of phlebitis were produced, but none of the phenomena of phlegmasia dolens. But in another series of cases we find that phlebitis may be produced, and equally extensively, by vitiating the general mass of the blood; and here, in addition to phlebitis, we have superadded all the phenomena of phlegmasia dolens. The conclusion, therefore, that appears to me to be inevitable is, that phlebitis occurring as a local disease, and from the operation of a local cause, is never associated with the phenomena of phlegmasia dolens, nor under any circumstances can give rise to it; but that, when it arises from, or in connection with, constitutional causes, or from local causes calculated simultaneously to infect the blood generally, then that the lesion of the veins is very generally accompanied with the symptoms of phlegmasia dolens. The effective cause, therefore, of the phlebitis, as of the crural affection, is the constitutional condition out of which both have arisen; and phlebitis stands in no other relation to the ætiology of the disease than in that of intensifying the local actions going on in the affected extremity, by concentrating upon it the general or diathetic conditions which may have given rise to it. Thus regarded, however, phlebitis plays a prominent, although subordinate, part in the phenomena of the disease. It intensifies the morbid actions going on in the affected limb, but at the same time it does not create them; it is strictly a secondary effect, and, like the other lesions of the extremity, is a common consequence of the same constitutional or morbific causes which may be in operation, and upon which they both mutually depend.

Conclusion. It thus appears to me that the conclusions deducible from physiological research essentially harmonise

with those drawn from clinical experience, and so far-inasmuch as they mutually affirm and support each other, and point to the blood-origin of the disease-they furnish a strong argument in favour of the correctness of the views I have ventured to submit to you in relation to its nature and pathology. It now, therefore, only remains for me to show how far a recognition of these views tends to more enlarged and correct principles of treatment; and this, the last and most important topic to be considered, I propose to take up and elucidate in the ensuing and final Lecture.

LECTURE III.

APPLICATION OF PATHOLOGICAL AND PHYSIOLOGICAL INFERENCES TO THE PREVENTION AND CURE OF PHLEGMASIA

DOLENS.

Delivered December 2nd, 1861.

MR. PRESIDENT, AND GENTLEMEN, -I proceed, in the last place, to the practical application of the views unfolded in the preceding lectures to the prevention and cure of phlegmasia dolens. I have endeavoured to show, in what has preceded, that, whether we look to the broad evidence of clinical experience, or to the more precise evidence of physiological research, we are equally led to recognise the important fact, that the essence of the disease consists, not in any particular local lesion, whether phlebitis or otherwise, but in an assemblage of local lesions attended with constitutional disorder of varying types and tendencies, having a common origin in an abnormal or vitiated condition of the blood, and that the causes of this abnormity are of a very widely spread and dissimilar character. So extensive, indeed, is the range of morbid actions conducive to the disease, that I venture to repeat, that there is scarcely a febrile movement capable of being inaugurated in the economy which may not, under certain circumstances, give rise to it. The first great practical lesson, therefore, to be learnt from the foregoing investigations, is the importance of studying the disease in connection with all those forms and types of febrile disturbance which are liable to occur during the puerperal