Turns out that it was due to a disk failure. Eventually, the
entire system slowed to a crawl; it required a complete reformat
of the disk to fix the problem.
I upgraded to Safari 3.0.2. The speed problem with this script is
now fixed.
tell application "Mail" to content of every signature
I can't recall whether I encountered that slowdown before or after I
upgraded to Safari 3.0, but I know that after the disk was
reformatted and I upgraded to Safari 3.0.2, the problem went away.
Before reformatting, the entire system slowed to a crawl, and nothing
else helped; that's the reason for the reformat. If that hadn't
helped, I would have wound up replacing the hard disk.
-- Michelle
--
"Democrats wrap themselves in the constitution and burn the flag
while Republicans wrap themselves in the flag and burn the
constitution."