The tumour which comes next to be described is decidedly malignant. It is the Encephaloid, or Medullary Sarcoma. Although these tumours have been called encephaloid and medullary, it must not be understood that their intimate structure has any relation to that of the brain or marrow; for this reason the old term _fungoid_ is perhaps a preferable one, since it leads to no false notion as to their nature, while it expresses a condition which at one time or other is remarkably characteristic of them. This tumour consists of a homogeneous matter, resembling the substance of the brain in colour and consistence It rarely has a distinct cyst; occasionally it is subdivided by membranous bands. It is always soft, though often more so in some parts than in others; portions of it being frequently so much softened and broken down as to resemble thick cream in consistence, and these are generally of a darker colour, from being mixed with a greater or less quantity of effused blood. Partial or universal softening only occurs after the tumour has existed for some time, for in its original state its structure and density are uniform throughout; and, on making a section of it, some few drops of blood may escape from vessels, the coats of which are of a very delicate nature. Some of these vessels seem to give way, in consequence of the process of softening, for we frequently meet with fluid blood, or masses of fibrin, in the midst of the pulpy matter; and, when the softening has been extensive, the blood is diffused throughout the whole substance of the tumour, so that it will appear to be chiefly, or entirely, composed of effused and degenerated blood, as here represented. [Illustration]