224 PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



OIV SEMPER'S ITIETIIOD OF MAKIIVG DRY PREPARATIONS.* 



In the Journal of the Eoyal Microscopical Society of London for 

 August last it is stated that " Herr Semper recently exhibited to the 

 Wiirzburg- Society some zoological and anatomical preparations which 

 had been prepared by a new method for dry preservation. After being 

 hardened in a solution of chromic acid [the strength to be regulated 

 according to the delicacy of the object and varying from one-half to one 

 per cent.], the objects are placed in alcohol [95 per cent, will answer] to 

 remove the water and afterwards steeped in oil of turpentine and finally 

 dried. The tissues, while drying, are permeated by innumerable small 

 air-bubbles, and in consequence the preparations retain their origin aj 

 form without sensibly shrinking, while in color they assume a white tint 

 similar to a gypsum model. The finished preparation, which is almost 

 pure white, and which i^ossesses a firm, leathery consistency, may be 

 painted with colors in i)arts as may be required for teaching purposes. 

 The preparations ijroduced were partly complete animals — mussels, 

 aunelida, and so forth — with the viscera of various vertebrate and inver- 

 tebrate animals. A preparation of a cat's eye showed that, after drying, 

 the position of the parts — the leus, ciliary processes, and so forth — 

 underwent no change. A microscopical preparation of brain, treated 

 on this method, proved that still simpler microscopic relations were 

 retained after the drying — and, particularly with carmine coloring, could 

 be distinctly recognized. 



Herr v. Kolliker pointed out the advantage to be derived from this 

 method, especially the possibility^ of adapting the preparations for 

 special demonstration by painting.f 



The utility of a method of preparation of this kind for moderately- 

 sized animals, usually treated as alcoholics, will at once be apparent. It 

 would be possible to paint the subject either in the natural colors of life, 

 or, in the case of anatomical preparations, to indicate the parts by the 

 use of arbitrary, conventional tints. While these preparations would 

 be readily combustible, they would be light and absolutely free from the 

 attacks of Dermestes, those well-known museum pests. As a most in- 

 structive method of making dry preparations for museum display, either 

 of whole animals or of their anatomy, it certainly deserves a trial, as it 

 is a much neater and cleaner method than the Wickersheimer plan, in 

 which glycerine enters as an important element, and which would be 

 objectionable because the object could never be thoroughly dried, but 

 would always be sticky and disagreeable to handle and liable to soil the 

 shelves of the museum cases. In order to make the preservation effect- 

 ual, after dehydration in 95 per cent, alcohol, which is strong enough 



* Abstract, with remarks by J. A. Eyder. 



tVerliandl. Phys.-Med. Gesell., WUrzbnrg, XV, 1881, S. B. IX. 



