The spirituous liquor be from 16 to 22° of the areometer of Baumé; stronger, it destroys the colors of animals; it is used at 22° only for mammifers. All spirituous liquor are equally good. The color less are preferable.
Before wrapping vertebrated animals in cloth, an incision should be made in the breast and abdomen, to let the liquor run in the inside of the body. The opening should be very small, in the side, and not in the middle. If the mammifers are large, it is well to pour the alchool in the intestinal canal, either by the mouth or anus.
It is well to renew the liquor, after the animal has remained in it some time: this precaution is absolutely necessary, when there is several animals in the cask; if it is neglected, they may corrupt.
It is well to arrange the animals so that they may not touch the bottom of the cask.