As "in situ". They are two words meaning basically "in place", or 
where the thing in question normally is found. Most correctly, they 
should be italicized, since they are in a foreign language (Latin).
To be rant-and-raveful, hyphenating "in situ" is just another outcome 
of the abysmal language education in all but a few American schools 
(I used to think undergrads wrote like functionally illiterate 
middle-school kids, until I took up editing pieces written by Ph.D.s).

Phil

>I know this is trivial, but what is the proper way to write these two
>words?
>
>R. Cartun

-- 
Philip Oshel
Supervisor, BBPIC microscopy facility
Department of Animal Sciences
University of Wisconsin
1675 Observatory Drive
Madison,  WI  53706 - 1284
voice: (608) 263-4162
fax: (608) 262-5157 (dept. fax)