350 THE AMERICAN MONTHLY [Dec, 



Preserving Objects of Natural History : Microscopical 



Objeas. 



By ARTHUR M. EDWARDS, M. D. 



NEWARK, N. J. 



The editor of one of the natural history magazines says that 

 he " wants alcoholic specimens." 



Now whilst I could send him alcoholic specimens of natural 

 history in quantity, I wish to say something about the use of 

 alcohol in preserving such objects. I do not use alcohol at all; 

 except for drinking in the shape of wine, whiskey and beer. 

 But I preserve specimens of natural history by a better and 

 cheaper mode. I do not use alcohol; first, because it is dear; 

 second, because it evaporates; and, lastly, because it contracts 

 objects immersed in it and renders them colorless. Besides it 

 is not a good preservative. I have found, to my sorrow, the 

 snakes immersed in alcohol, and strong alcohol at that, after a 

 time fell to pieces. Insects it does pretty well with, and ani- 

 mals will keep in it. But I use a watery solution of true 

 salicylic acid. When I speak of true salicylic acid I do not 

 mean the salicylic acid that is made from carbolic acid, for that 

 is unstable and cannot be us* d in preserving objects of natural 

 history, nor in medicine in which salicylic acid is so useful 

 curing rheumatism. True salicylic acid is made of oil of win- 

 tergreen, and is in white, silk\^ needles. Artificial salicylic acid 

 is opaque and a mass of white minute crystals ; besides it does 

 not taste the same as the true acid. It is barely soluable in 

 water and I use a solution in water as a preservative. It is 

 cheap, also, much cheaper than alcohol. It does not evapor-. 

 ate, and, although it freezes in winter, whilst alcohol does not, 

 this is a minor objection to its employment. Besides it does 

 not render the objects immersed in it opaque. It keeps some 

 colors, likewise it is anti-parasitic and destroys bacteria ; be- 

 sides, it is not poisonous. Siijce I first used it, fifteen years 

 ago, I have never had a failure. It preserves the most delicate 

 objects. Bacillariacese (Diatomacese) are preserved well in it, 

 and other microscopic objects also. Watery solution of car- 

 bolic acid may be used, but that is poisonous and smells badly, 

 whilst salicylic is odorless. I think it will recommend itself to 

 ^,11 who use it, and I should like it tried, But remember that 



