[Histonet] Davidson's fixative

[RSRICHMOND <@t> aol.com]

>>1500 ml. 37% formaldehyde
2250 ml. Absolut [sic] alcohol [but I wouldn't pay the beverage tax for 
premium vodka!]  
75 ml. glacial acetic acid
2250 ml. tap water
eosin to color (not powder)<<

This formula for Davidson's fixative isn't real close to the "modified 
Davidson's fixative" used by Moore and Barr (see my Web page about it for 
references):

two parts 37% formaldehyde
three parts 100% (or 95%) alcohol
three parts tap water
one part glacial acetic acid
eosin to color

As John Kiernan pointed out on this list a long time ago, a rather wide range 
of composition of this type of fixative will give about identical results.

The proprietary fixatives mentioned are indeed secret formulas. It seems 
absurd both from a scientific and a financial viewpoint to use them, but who among 
us fathometh the wisdom of Management?

In the surgical pathology laboratory, my major use for Davidson's fixative is 
as a clearing fixative to find mesenteric lymph nodes in colon resection 
specimens. My personal opinion is that use of clearing fixatives in this situation 
is a standard of care. In colon cancer positive lymph nodes are sometimes 
very small, and finding even one positive lymph node often results in a patient's 
receiving postoperative chemotherapy and maybe having their life saved by it.

Bob Richmond
Samurai Pathologist
Knoxville TN and Gastonia NC