Definition of "gein"

Hence, a most interesting conclusion—without salts and gein we have no vegetable production. The gein in solution is essential to fruit, and yet, without the salts, the insolubility of gein would leave the soil barren.

1843 January 9, Henry Bidleman Bascom, “Glance at the Natural History and Philosophy of Agriculture […]”, in Thomas N. Ralston, editor, Posthumous Works of the Rev. Henry B. Bascom, […], volume 2, published 1856, page 201

The humic acid and other similar acids (ulmic, geïn, &c.) have a very strong affinity for ammonia, which itself is essential to the nourishment of forest growth, as plants have only a limited power of assimilating the free nitrogen of the air.

1893, John Nisbet, Soil and Situation in Relation to Forest Growth, page 10

Thus with a free supply of air the residue is mainly humin; with less air it is ulmin; and when air is excluded it is gein.

1907, Philip R. Björling, Frederick T. Gissing, Peat: Its Use and Manufacture, page 6