Word of the day is Pristine ('pris-"tEn, pri-'stEn)  (adjective) 

1 : belonging to the earliest period or state : ORIGINAL
2 a : not spoiled, corrupted, or polluted (as by civilization) : PURE b : fresh and clean as or as if new

Example from the New York Times :

The word pristinehas appeared in 332 Times articles over the past year, most recently in " House Dust Yields Clue to Asthma: Roaches "on April 7, 2009.

Asthma is the most common chronic disease of childhood, one that strikes the poor disproportionately. Up to one-third of children living in inner-city public housing have allergic asthma, in which a specific allergen sets off a cascade of events that cause characteristic inflammation, airway constriction and wheezing.

Now, using an experimental model that required leaving the pristine conditions of the lab for the messier ones of life, a team of scientists from the Boston University School of Medicine have discovered what that allergen is.