A prognostic significance often attaches to the accurate estimation of hemoglobin at intervals after removal of malignant tumors. A very convenient method for the ready estimation of hemoglobin is afforded by the Tallquist color scale. It can be practised at the bedside and is sufficiently accurate for the surgeon’s general purposes. THROMBOSIS. Thrombosis is a term applied to the formation of a _thrombus_--_i. e._, a clot within the cavity of the heart or one of the bloodvessels--the term being limited to coagulation of blood within these natural cavities, and without specifying the exciting cause of the same. A clot so formed is called a thrombus. To be accurate, a distinction should be made between a thrombus, which is caused always before death--or, rather, during life--and the _clot_, which is essentially a postmortem affair. Our application, then, of the terms “thrombosis” and “thrombus” refers solely to that which takes place during life. In order to appreciate the conditions which lead to thrombosis it is necessary to fully appreciate the reciprocal conditions which must normally be maintained between the circulating blood and the walls of the vessels in which it flows. Fluidity of blood depends always upon integrity of the vessel wall. As long as its lining membrane is absolutely undisturbed and normal, moving blood will never coagulate within it, and the only thrombi that may be met within it are those which are propagated from a distance. Coagulation of blood is, for the main part, associated with the peculiar properties of fibrin.