Pakkek. — On preserving Cartilaginous Skeletons. 263 



improved both in appearance and in usefulness for museum and lecture 

 purposes by being painted and varnished — the hearts, e.g., receive the con- 

 ventional blue and red hues. Distemper colours mixed with a solution of 

 shellac in methylated spirit seem to answer very well. 



For brains, my present experience seems to show that my method is 

 inferior to Giacomini's,* but the number of experiments made is hardly 

 sufficient to justify a very positive opinion. Anyhow, I do not expect to 

 effect much improvement in this particular direction ; the series of brains 

 prepared by my colleague Dr. Scott, by Giacomini's method, could not easily 

 be bettered. 



4. Invertebrate exoskeletons. A modification of the above method appears 

 to be very useful for Crustacea, Echinodermata, and other invertebrates with 

 hard exoskeletons. The internal organs are first, as far as possible, 

 removed, and the specimens are then placed in glycerine fluid for a few days ; 

 they are then well drained, and after a few days -dipped into thin size, kept 

 as nearly as possible at the ordinary temperatm-e of the an- : this is done 

 two or three times, and has the effect of producing a good surface ; a coat 

 of varnish may afterwards be applied or not according to circumstances. 

 For the larger Crustacea this method appears to be very successful ; the 

 chitinous parts retain their flexibility, so that the risk of injm-y to the 

 specimen is greatly diminished, and the natural colours are retained, in 

 many cases, perfectly. A female Halimus hectori, for instance, with eggs 

 attached to the swimmerets, has the general dark colour of the body 

 unaltered, instead of being nearly colourless as in ordinary dried speci- 

 mens, and the bright scarlet eggs have merely become a shade or two 

 darker, then* form and trauslucence being unchanged.! 



5. Skins of fishes, amphibia, etc. From one or two experiments, I think 

 the method described in the preceding paragraph is likely to prove very 

 useful for the preparation of skins of fishes, etc., for stuffing. The glycerine 

 fluid must, however, be of only liaK the usual strength, i.e., one part of 

 glycerine to two of water. The fish is skinned while perfectly fresh, and 

 the skin prepared as above and then stuffed. Some of the colours appear 

 to be retained very well by this method, but I have not yet succeeded in 

 retaining the more delicate shades, such as the spots of the trout and the 

 pink tints of the red cod {Lotella bacchus). There is certainly one great 



* Journ. of Anat. and Phys., Jan., 1879. 



t I believe that my friend Professor Haddon, when curator of the Cambridge 

 Museum, employed glycerine for preserving Crustacea, but I know nothing of the way in 

 which it was used. In Dr. Carpenter's fine collection of starfish, the colours are 

 beautifully preserved by means of glycerine, but the specimens are enclosed in glass cells, 

 which are expensive and troublesome. 



