Dr MacCulloch on Perfumes for Preventing Mouldmess. 33 



I had commenced some trials on Wood on the same principle, 

 with the view of preserving it from what is called the dry-rot,- 

 and, as it seemed to me, with effect. But as I have now no hopes 

 of pursuing this subject, I am glad to have an opportunity, by 

 your means, of putting it into better hands. A cheap oil, of 

 course, would be required for operations so extensive as this. 



The next substance that I shall point out is Paste, which is 

 a very perishable article. Alum, which is used by the book- 

 binders, although it preserves that most necessary substance 

 longer than it would remain useful without it, is not very effec- 

 tual. Rosin, sometimes used by shoemakers, answers the pur- 

 pose better, and appears to act entirely on this principle. It is ? 

 however, less effectual than even oil of turpentine. Lavender, 

 and the other strong perfumes, such as peppermint, anise, and 

 bergamot, are perfectly effectual, even in a very small quanti- 

 ty ; and paste may thus be preserved for any length of time. 



Your mineralogical readers in particular, who have frequent 

 occasion to use paste for their labels in very small quantities, 

 and where the trouble of thus making it on every fresh occa- 

 sion is inconvenient, will be glad to know that this useful article 

 may be made to keep, even for years, always ready for use, and 

 subject to no change. 



That which I have long used in this manner is made of flour 

 in the usual way, but rather thick, with a proportion of brown 

 sugar, and a small quantity of corrosive sublimate. The use 

 of the sugar is to keep it flexible, so as to prevent its scaling off 

 from smooth surfaces ; and that of the corrosive sublimate, 

 independently of preserving it from insects^ is an effectual check 

 against its fermentation. This salt, however > does not prevent 

 the formation of mouldiness. But as a drop or two of the es- 

 ' sential oils above mentioned is a complete security against this$ 

 all the causes of destruction are effectually guarded against, 

 Paste made in this manner, and exposed to the air, dries with- 

 out change to a state resembling horn ; so that it may at any 

 time be wetted again^ and applied to use. When kept in a close- 

 covered pot, it may be preserved in a state for use at all times. 



This principle seems also applicable to the preservation of 

 seeds, particularly in cases where they are sent from distant 



