Formic Acid
2 of the 7 encyclopedias on this shelf carry an entry for Formic Acid. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
an important substance in organic chemistry. It is composed of carbon, hydrogen, and oxygen in the atomic proportions of one, two, and two. It is found in a natural state in ants, caterpillars, leaves of fir, and pine trees, and in the common nettle. It occurs also in certain fruits. The acid may be obtained on a small scale by crushing the bodies of red ants and distilling the mass with water. It is obtained in commercial quantities by heating crystals of oxalic acid with glycerine and distilling the product. Pure formic acid is used in small quantities for medicinal purposes. It is a disinfectant and a preservative. It is used, also, in the manufacture of fruit essences. The acid is used largely in the dyeing and tanning trades, for which purposes it has displaced acetic acid in part. Used to dye silks, it produces a beautiful sheen. It gives mercerized cotton the rustling effect of silk.
Collier's New Encyclopedia (1921)
HCHO2, or H:CO: OH, a monobasic fatty acid, which derives its name from the circumstance that it was first obtained by distilling ants. It occurs in the animal and vegetable kingdoms, especially in the red ant, Formica rufa. When an ant walks over moistened blue litmus it turns it red. It exists also in certain caterpillars, in several secretions of the human body, as in blood, in urine, in the fish-juice, and in perspiration. It is also found in the juice of the stinging nettle, and in commercial oil of turpentine that has been exposed to the air, and in certain mineral springs.