RE: Long term "museum" storage

<< Previous Message | Next Message >>
From:"R.Wadley" <>
Date:Thu, 16 Sep 1999 15:31:03 +1000
Content-Type:text/plain; charset="us-ascii"

	Dear All,

	Running a bit late with this reply.
	I prefer Wentworth's method to Kaiserling, but the principle remains the
same, tissue must be well fixed, correctly buffered, & apprpriately mounted.
	Colour will only remain in a specimen if it is an air tight container and
the fluid is slightly alkaline (pH 7 - 7.5).  Above pH 8.5 there is good
colour preservation but the specimen starts to macerate, below pH 6.5 the
colour begins to deteriate, fading increases with acidity.
	Treatment with ethanol is detrimental to colour preservation.
	A well fixed specimen (at least 1 month) of a known weight, with an
appropriate pH, is mounted in Wentworths 5:
	Formaldehyde (40%)		20ml
	Sodium Acetate			40 g
	Tri-sodium phosphate		1 g
	Glycerine				200 ml 
	Distilled water			1000 ml
	pH to 7.5.
	After several days the pH is checked, if it is stable, 3 g of sodium
hydrosulphite is added per 1000 g of specimen.  This is important, the
quantity of Na hydrosulphide is related to the specimen weight not the
volume of the fluid in the container.
	Over time the pH will change so this fluid will need to be changed
regularly (2 - 5 years).  If fading occurs then a fresh change of solution
wll generally retore the specimen to its former glory.
	As a last resort for badly faded specimens Proger's Sol'n can be used;
	Formaldehyde (40%)		82 ml
	Pyridine				16 ml
	Sodium dithionite			32.7 g
	Di-sodium hydrogen sulphate		22.7 g
	Potassium di-hydrogen phosphate	1.8 g
	Distilled water			1000 ml
	Mix & dissolve these ingredients then add 755 ml of glycerine.
	My notes state that this will restore colour to old faded specimens but if
the specimen is ever exposed to air it will fade irreversibly.
	Note the addition of glycerine is to eqaulise the refractive index of the
solution to that of the perspex or glass container.


	Rob W.

R. Wadley, B.App.Sc. M.L.S, Grad.Dip.Sc.MM
Laboratory Manager
Cellular Analysis Facility
School of Microbiology & Immunology
UNSW, New South Wales, Australia, 2052
Ph (BH) 	+61 (2) 9385 3517
Ph (AH)	+61 (2) 9555 1239
Fax 	+61 (2) 9385 1591

<< Previous Message | Next Message >>