You couldn't help but be impressed.

One of the few survivors is Wallace Pannier, 76, who remembers standing in a Frederick County field watching sheep shot with what the Army called a "nondiscernible bioinoculator" -- a dart gun. The bosses demanded a dart so fine that it could penetrate clothing and skin unnoticed, then dissolve, leaving no trace in an autopsy.

"If the sheep jumped, that meant people were going to jump, too," said Pannier, now living a quiet life tending his flowers and shrubs in Frederick.

...

"Twenty-five seconds after it was shot, the sheep just fell to the ground," said Baronian, 73. "It didn't bleat. It didn't move. It just fell dead. You couldn't help but be impressed."

http://cryptome.org/bio-secrets.htm