215. Os de corde serui: i.e. the bone that is in the heart of the deer; it is cold and dry, but the degree is not to be found in Platearius' book; it occurs in the left side of the heart, and it is generated from the blood of the heart itself; it is a soft substance at first, until it hardens into a sort of bone; a similar bone occurs in the heart of the goat, and is sold as being this bone. The difference between them is that the bone of the heart of the deer is off-red, while the bone of the heart of the goat is white and soft; the bone of the heart of the deer retains its efficacy for thiry years, if it be dried in the sun first; it has the virtue of