When the parts have been dried by one of the processes just mentioned, if they be abandoned to themselves, they would become injured in a little time by humidity and insects. There remains, then, some care to be taken before depositing them in a cabinet; they should be washed in a liquid containing a preparation of arsenic, or of sublimate, or rather by applying to them a varnish containing one or both of these substances. We shall not reconsider here the compositions of varnishes, having already given several formulæ for them when speaking of Swan’s method, and we shall have occasion to refer to them again when passing in review the different methods of preparing objects of natural history. _Preservation in liquids._--Anatomical parts are also preserved, and more advantageously, in liquids. We shall now consider the acids, or acidulated waters, alkalies, salts, oils, spirituous or alcoholic liquors; expose their advantages under certain circumstances, their inconveniences under others. When acids are employed for preserving anatomical parts in their natural state of suppleness, caution must be used to dilute them, with a sufficient quantity of water, so that they may not corrode or harden the parts. In general, it is advantageous to allow them to remain for the first few days, in a very weak acid, and not place them in the prepared liquor, until they have ceased to make any deposit. The objections against muriatic acid are, that it renders the surface of the parts gelatinous, gluey, and transparent; of nitric acid, to tarnish and contract them; of sulphuric acid, to bleach them. All these acids decompose the parts when they are not sufficiently diluted with water; they allow the liquor to putrefy or to freeze, and break the vessel when they are too weak. The proportions are indicated by experience, and depend upon the nature of the part which it is intended to preserve. It is those parts in particular which are loaded with fat, that are best preserved in acid liquors. In general, little use is made of liquors which hold alkalies in solution: the carbonates of commerce are preferable; and these are used with advantage, when it is necessary to keep for several days, before dissection, animal parts in which corruption has already commenced. Those salts derived from the combination of acids and earths, the alkalies or metals, may be employed like the acids diluted with water. They are not subject to the same objections. The nitrate of potash, the muriate of ammonia, those of lime, or of soda, are very proper for preserving pieces of myology; they appear even to reclaim the red colour of the muscles, when these solutions are strongly saturated; but, then, they are liable, some of them, to liquify, others, to effervesce or to chrystalize upon the sides of the jars, and even on the surface of the parts themselves, which is a very great inconvenience when it is wished to expose the parts to view.