Heart, a hollow muscle of a conical form, situated at the bottom of the thorax or breast: its basis is turned towards the right, and its point towards the left side. The former, whence the great blood-vessels take their origin, is covered with fat, and has two hollow appendages, called auricles, from their resemblance to an ear. The whole consists two cavities, which are separated from each other by a thick muscular septum: One of these is called the right, and the other the left ventricle.

The heart, which may be considered as the most powerful muscle in the animal body, serves to faci-litate the motion or circulation of the blood, which is communicated to the different parts of the frame, by means of various arteries and veins. These, however, it is the province of anatomy to describe; and as that subject: does not enter into our plan, we trust this brief explanation will suffice.