Hi Shireen, You mentioned that the museum specimens you saw were STORED in 70% isopropyl alcohol. That is a good long-term STORAGE solution for most types of specimens, including those for museum display, for eventual dissection, and for histological studies, but NOT for materials intended for DNA or other molucular studies. However, long-term storage and initial preservation (or fixation as we call it in histological circles) are two different matters. Tissues for DNA work are best preserved by direct immersion in strong, 95% to 100%, ethanol (ethyl alcohol), and best stored in the same medium. However, this kind of tissue fixation, like most types of fixation, is a trade-off. In this case you gain DNA stability at the expense of cellular detail and general tissue morphology. If histological study is the intended purpose, then formalin, or any of several other aqueous fixative agents, should normally be used. These compounds form molecular cross-links between protein molecules, and produce other submicroscopic effects which stabilize tissue components at the microscopic level. Alcohol, while it stabilizes DNA very well, also rapidly extracts water from the tissue, causing cells to shrink and become misshapen. It also dissolves various substances out of the cells, which would be stabilized by a good fixative; and it hardens tissues excessively. However, once the tissue is properly fixed in something like formalin, it can then be transferred to 70% alcohol, safely stored without cellular damage, and later used for histological studies. If electron microscopy is intended, then neither alcohol nor formalin is suitable, and other fixatives, such as glutaraldehyde, must be used. So, there is no general preservative that is suitable for all purposes, and you have to know up front what the tissue will be used for, in order to preserve it properly. There are any number of biological supply houses which sell dissecting instruments and supplies. A few are: PGC Scientifics 9161 Indistrial Ct. Gaithersburg, MD 20877 301-840-1111; 800-424-3300 Fisher Scientific (offices in Atlanta, Cincinnati, Chicago, Dallas, Denver, Houston, Los Angeles, New York, Orlando, Philadelphia, Pittsburgh, Puerto Rico, San Francisco, St. Louis) Main Headquarters: 711 Forbes Ave. Pittsburgh, PA 15219-4785 412-562-8300 Cole-Parmer Instrument Company 625 East Bunker Court Vernon Hills, IL 60061-1844 800-323-4340 Baxter Diagnostics, Inc. Scientific Products Division (offices in Atlanta, Boston, Charlotte, Chicago, Cincinnati, Columbus, Dallas, Denver, Detroit, Honolulu, Houston, Indianapolis, Kansas City, Los Angeles, Minneapolis, New Orleans, New York, Ocala, Phoenix, Pittsburgh, Puerto Rico, St. Louis, Salt Lake City, San Francisco, Seattle, Washington DC) Main Offices: 1430 Waukegan Road McGaw Park, IL 60085-6787 800-234-5227 A. Daigger & Co. 199 Carpenter Ave. Wheeling, IL 60090 800-621-7193 Connecticut Valley Biological 82 Valley Road P.O. Box 326 Southampton, MA 01073 (413) 527-4030 This last-listed place is a smaller company, and has a lot of very inexpensive student-grade instruments. Regards, Paul M.