98 THE AMERICAN MONTHLY [March 



Preservation of Library Mucilage. — Tha recent discus- 

 sions, in Thk Microscope and elsewhere, of methods for 

 preparing- permanent mucilag^es and pastes for the library' 

 or study table, seem to leave little need of addition, except to 

 g-ive a caution that salicylic and carbolic acids, lately rec- 

 ommended as preservatives by a very hig-h chemical au- 

 thority, are wholly unsatisfactory. Antiseptics of this 

 class soon turn the whole stock to a red color which is said 

 to be due to action upon the metal of the brushes com- 

 monly used in the mucilag-e bottle. 



For those who prefer an off-hand method wholly free 

 from the delay and trouble of making- up a special formula 

 the camphor method is probably the best. You simply 

 drop a lump of camphor, about as larg-e as a bean or half 

 of a chestnut, more or less, into the bottle of mucilag-e, and 

 then use and replenish the siipply just as if the lump was 

 not there. It does no harm there, but keeps the solution 

 so saturated with camphor that it cannot mould or fer- 

 ment. When the supply of mucilag-e becomes low, you 

 drop in some g-um Arabic powder, and pour in and stir in 

 some cold filtered water, and it is ready to use in two or 

 three minutes. When you happen to notice, after some 

 months, that the piece of camphor is very small, you drop 

 in another piece. And that is all. I have used this method 

 a g'reat many years, and have never seen it fail. 



For Moistening Envelopes, postag-e stamps, and g-um- 

 med pasters g-enerally, I have found, after trying- also var- 

 ious fancy arrang-ements that have been introduced, noth- 

 ing- so practicable for g-eneral library use (excluding- per- 

 haps some business uses where the employment is almost 

 constant) as a second mucilag-e bottle and its brush, sup- 

 plied with filtered water. A mere trace of g-elatin or g-um 

 added to the water makes it more manag-eable, by g-iving- a 

 little body to it; thoug-h this is by no means necessary, 

 and thoug-h it g-reatly hastens the deterioration of the stock 

 by keeping-. A lump of camphor floating- on the liquid, as a 

 preservative, will, in either case, keep it in a neat condi- 

 tion much long-er than without. It oug-ht to be no long^er 

 necessary to say a word in favor of some such expedient in- 



