3. The points 1 and 2 being so well balanced that the specimen is in a fit state--after many months — either to be treated as a specimen shown in fluid, or to be mounted by the process of taxidermy.
4. The comparative cheapness and facility of carriage of the preservative medium.
In trying to obtain all these advantages there seem almost insuperable difficulties in the reconcilement of these diverse conditions.
Dr. A. Guenther, F.R.S., the eminent, ichthyologist and Chief of the British Museum, recommends, in his new book, that pure or rectified spirits of wine (56 per cent. over-proof) be the only thing used for fishes, for permanent preservation in glass jars or tanks, and this even for ordinary fishes 3 ft. to 4 ft. in length, or even up to 6 ft. in length, if eel-like. "Proof" spirit (containing only 49 per cent. by weight of pure alcohol as against 84 per cent. contained in rectified spirit) is, says Dr. Guenther, the lowest strength which can be used.
These will then stand as
No. 19. — Rectified Spirits of Wine (56 per cent. over-proof),
and
No. 20. — Proof Spirits of Wine.
If a spirituous solution is absolutely required, I would substitute for pure spirits of wine methylated spirit (alcohol containing a certain percentage of impure gum or undrinkable wood spirit) as being cheap and sufficiently good for some purposes. It will not, however, bear any diluting with water; it must stand, therefore, as
No. 21. — Methylated Spirit (undiluted),