A closely allied topic to that above considered is the subject of _thrombophlebitis_. This means, in effect, inflammation of one or more veins, which is directly due to the presence therein of thrombi. Such a condition is, in its strict sense, an inflammation, since it is always an infectious process. If in the veins of a non-infected region simple thrombi form, they may be occluded by organization of the included masses, but such a process never extends beyond the immediate area involved. On the other hand, if the process is essentially an infectious one, either from without or from within, then both vessel and its contained thrombi succumb completely to the infectious process, which is also essentially a spreading one; and this is limited only by mechanical barriers, by conservative suppuration, or often only by the life of the individual. Excellent examples of thrombophlebitis are seen in the involved uterine sinuses in cases of puerperal septicemia, and in the cranial sinuses after infected compound fractures, or particularly after disease originating in the middle ear has extended to them. Thrombosis is, at times, a distinctly surgical condition, and often a surgical complication of febrile and other diseases, especially typhoid, in which it constitutes a serious complication and prolongs convalescence for a period of several months. If foreseen it can scarcely be prevented, and when present calls for treatment varying with the location of the lesion and the exciting causes. In the earlier stage anything like rude manipulation or massage is very unfortunate, since soft clots might thus be broken up and distributed to other parts of the body. Absolute physiological rest combined with the application of silver ointment, of ichthyol-mercurial ointment, which should be covered with some non-absorbent material, will probably give the best results. If the lower limbs are affected it may be well to elevate the feet so as to favor return of blood through vessels not yet obstructed. After a certain length of time the thrombi may be regarded as at least adherent if not organized, and massage will prove an important remedy, since by it the lymphatics will be better enabled to take up the fluids which have leaked from the bloodvessels and produced the edema which always characterizes these cases. Sluggishness of circulation is nearly always followed by more or less laxness of tissue, or actual hypertrophy, and a limb thus involved may never regain its original size or flexibility. Veins once compromised, if not occluded, frequently become varicose, or varicosities develop in adjoining veins and still further complicate the case. For such difficulty the measures discussed in the chapter on the Veins may be later required.