In every fresh case of thrombosis or thrombophlebitis great care should be taken in order that by no means shall the clots be disengaged and float away. The dangers correspond to those existing in variocele and nevi, often treated by the older methods of injection of coagulating material. In one instance reported, a child died within half an hour after the injection of an iron salt into a small nevus of the face. Coagulation was excited to a point far beyond the limits intended. _Thrombophlebitis is essentially a surgical condition_, occasionally terminating favorably by suppuration and spontaneous evacuation, but calling for surgical intervention whenever it can be recognized and the parts are accessible. The principles of treatment of these conditions are positive and unmistakable. They comprise evacuation of the infective material and disinfection of the involved cavities and tissues. Thus, in sinus phlebitis--_i. e._, thrombophlebitis of the lateral sinus--it has been made practicable not only to open the sinus in the mastoid region, but to expose the jugular vein in the neck, to ligate it, and to wash through from one opening to the other, effectually getting rid in this way of a long mass of infected thrombi. Only by such bold and radical measures in many of these instances may life be saved. EMBOLISM. Embolism means the _transportation of any material by which a bloodvessel can be occluded or plugged_ from one part of the vascular system to some other. The underlying idea is that of _transportation_ or carriage. An _embolus_ is anything so transported, without implying its exact character. The name is even applied to so unsubstantial an affair as a minute bubble of air, which, however, in a tube containing a circulating fluid is a possible source of considerable disturbance. A single bubble thus carried would, by itself, be a trifling affair, but when numerous bubbles are thus transported the result is such local disturbance as may lead to loss of function. Thus, _air embolism_, so called, may provoke profound, even fatal, disturbances, as, when, with the returning blood stream through the cranial sinuses or one of the large veins in the neck, when opened by accident or operation, air is sucked in, it is carried to the right side of the heart, whose action is perhaps completely perverted because of the new and strange substance which thus enters it, so different from that for which its lining membrane is prepared and to which it reacts. The _entrance of air into veins_, which constitutes in effect air embolism, has been in time past a bugbear to surgeons, but nevertheless is a source of probable danger when large venous trunks in proximity to the heart are thus exposed. Air embolism is certainly a rarity. On the other hand, those substances which figure most often as emboli are _vegetations from the valves of the heart_; _drops of fat_; _fragments of tumors_; _pieces of softened and disintegrated thrombi_; _foreign bodies_, as