The leaves are to be put into an earthen or glass vessel, and a large quantity of rain-water to be poured over them; after this they are to be left to the open air and to the heat of the sun, without covering the vessel. When the water evaporates so as to leave the leaves dry, more must be added in its place; the leaves will by this means putrefy, but they require a different time for this: some will be finished in a month, others will require two months or longer according to the toughness of their parenchyma. When they have been in a state of putrefaction for some time, the two membranes will begin to separate, and the green part of the leaf to become fluid: then the operation of clearing is to be performed. The leaf is to be put upon a flat white earthen plate and covered with clear water; and being gently squeezed with the finger, the membranes will begin to open, and the green substance will come out at the edges; the membranes must be carefully taken off with the finger, and great caution must be used in separating them near the middle rib. When once there is an opening towards this separation, the whole membrane always follows easily; when both membranes are taken off, the skeleton is finished, and it has to be washed clean with water, and then dried between the leaves of a book. Fruits are divested of their pulp and made into skeletons in a different manner. Take, for an instance, a fine large pear which is soft, and not tough; let it be neatly pared without squeezing it, and without injuring either the crown or the stalk; put it into a pot of rain-water, covered, set it over the fire, and let it boil gently till perfectly soft, then take it out and lay it in a dish filled with cold water; then holding it by the stalk with one hand, rub off as much of the pulp as you can with the finger and thumb, beginning at the stalk, and rubbing it regularly towards the crown. The fibres are most tender towards the extremities, and are therefore to be treated with great care there. When the pulp has thus been cleared pretty well off, the point of a fine pen-knife may be of use to pick away the pulp sticking to the core. In order to see how the operation advances, the soiled water must be thrown away from time to time, and clean poured on in its place. When the pulp is in this manner perfectly separated, the clean skeleton is to be preserved in spirits of wine. This method may be pursued with the bark of trees, which afford interesting views of their constituent fibres.