_Sinus thrombosis._--This complication is the one that is recognized as giving the best prognosis because it can be very readily recognized, and even exploration is warranted to make such diagnosis. It most frequently follows, or is associated with, acute infections of the middle ear and mastoid process. The most important symptoms are the chills and fever of a distinct septic type, and, as a rule, increasing in frequency. There is invariably a blood-picture of sepsis, namely, a very high leucocyte count and the polymorphonuclear type in marked excess. Blood cultures are, as a rule, positive of a bacteriemia. If the process has extended to the bulb and internal jugular vein, then one may feel a thickening or cord-like mass along the anterior border of the sterno-cleido-mastoid muscle. The fundus examination often reveals a choked disk, especially on the side where the thrombosis is located. A symptom recently described by Beck, of Vienna, and Crowe, of Baltimore, and proven by me to be of positive value in several cases, is the production or increase of a choked disk by compression of the healthy internal jugular vein. Urbanschitch has shown in quite a number of cases of sinus thrombosis that the blood-clotting time is very much enhanced. This of course is true of any case of bacteriemia or septic phlebitis anywhere in the body. I have proven this test to be of value to me in several cases of sinus thrombosis. The exploratory exposure of the lateral sinus is of distinct value, and the only fact to remember is to expose a sufficient area so that one is able to deal with the sinus in case it be opened accidentally, because such an accident when this precaution was not taken has led to serious consequences. The diagnosis of a thrombotic sinus when exposed is made first by its discoloration, usually of a grayish pink; secondly, it feels harder than normal and is not resilient when compressed, that is, it does not spring back. It, however, may be soft in case the thrombus has broken down; and in cases of parietal thrombosis it may spring back because there is blood circulating through it. One will at times find a small collection of pus about the sinus, a condition known as perisinus abscess, and in many instances of this condition the sinus itself is not thrombosed. The puncture of the sinus by a hypodermic needle and attempt to withdraw some blood, is not at present considered good practice owing to the danger of infecting a non-infected sinus. An incision is considered a wiser plan, and subsequently packing both sides (torcular and bulb) so they are shut off from the general circulation. There are many instances of secondary infection by embolism, either in or about the joints, and infection into the lungs, spleen, pancreas, etc., with the entire train of symptoms from such complications.