I'm told that under certain climatic condition-I believe arid with
little rainfall-a corps will exude a kind of fluid that forms an
impression around it.  This substance does not evaporate or disperse. 
This happens to a degree in all cases, but the ideal conditions are as above so
I'm told. What is this fluid called and what does the bodily process
entail?  I believe this can be helpful in determining the time of
death in certain cases.

The fluid which seeps from a dead body is called "purge fluid." It can
indeed be used in estimating time of death, and in determining other
facts about the body:

"Medical investigators look for various signs to help them estimate a
time frame -- usually a 2 to 4-hour window of time -- in which the
victim probably died. These signs may include the following:

Rigor mortis (the stiffening of the muscles that occurs shortly after
death)
Lividity (pooling of blood) 
Body core temperature 
Clouding of the corneas 
Evidence of a decompositional process 
Presence/absence of purge fluid 
Drying of the tissues. 

ThinkQuest Internet Challenge Library
http://library.thinkquest.org/TQ0312020/estimating_time_of_death.htm

"Sachs ends with information about some of the newest forensic
technology: forensic botany, in which plant life around corpses is
studied for clues, and  the study of 'dirty dirt' - the soil beneath
bodies that contains bodily fluids released from cadavers, much of
which contains microscopic clues about the person's demise."

Burlington-Edison Library
http://www.be.wednet.edu/Hs/library/corpse.htm

In an arid climate, a body may become desiccated to the point of
mummification as fluids are drawn from the body:

"In the Middle Horizon period (1400 to 1000 years ago) the dead were
wrapped in a seated, upright position (with the knees at the face)
within mummy bundles. The body was placed on a basket or gourd and
then wrapped with fabric. The positioning of the body and the fabric
bindings served to draw out the decomposing fluids of the body and,
with the dry conditions, resulted in the mummification of the body."

Death Online
http://www.deathonline.net/disposal/preservation/andean.cfm

The writer Patricia Cornwell refers to purge fluid in her novel "Black
Notice":

"Near the back, it illuminated a bottom row of cartons soaked with the
reddish purge fluid that leaks from the nose and mouth of a
decomposing body."

Book Reporter
http://www.bookreporter.com/reviews/0425175405-excerpt.asp

You'll find a mention of purge fluid in an episode of "CSI" entitled
"Lady Heather's Box" -- which, coincidentally, is scheduled to be
rerun this evening on CBS:

"NICK:  Whew.  No pain, no gain.  Purge fluid.

 CATHERINE:  D.U.N.S.

(Quick flashback to the neighbor in the apartment underneath.  He
looks up and
sees the large patch of liquid on the ceiling spreading and dripping. 
End of
flashback.  Resume to present.)

 NICK:  Dead Upstairs Neighbor Syndrome."

Twiz TV Television Scripts
http://www.twiztv.com/scripts/csi/csi315.htm

If you are interested in forensic pathology, you might want to check
out these excellent answers by my colleagues, knowledge_seeker-ga and
tutuzdad_ga:

Google Answers: Post-mortem human decay 
http://answers.google.com/answers/threadview?id=190457

Google Answers: Screenplay question---"corpse appearance after
twenty-five years in woods"
http://answers.google.com/answers/threadview?id=232696

Google search strategy:

Google Web Search: "purge fluid" + "death"
://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=%22purge+fluid%22+death

I hope this information is useful. If anything is unclear, or if a
link does not function, please request clarification; I'll gladly
offer further assistance before you rate my answer.

Best regards,
pinkfreud

to pinkfreud-ga. Thanks for the answers to my question. I did find the
word I was looking for - adipocere - in threadview 190457.