Swarming on the extremity of the branches among which the formicary is constructed, the defenders, projecting their terminal segments as far into space as possible, eject formic acid in the direction of the enemy.
"Tropic Days"
E. J. Banfield
In some cases it becomes changed in the body into formic acid, which should therefore be sought for.
"Aids to Forensic Medicine and Toxicology"
W. G. Aitchison Robertson
The root also contains malic, acetic, and formic acids, with a resin, tannin, starch, and mucilage.
"Herbal Simples Approved for Modern Uses of Cure"
William Thomas Fernie