These four alkaloids exist in combination in tobacco chiefly as malates and citrates.
Nicoteine is a liquid which boils at 267° C. It is separated from the other alkaloids of the group by distilling off the nicotine and nicotimine in steam and then fractionating the residue.
They possess a delicate Laticiferous layer of protoplasm, with numerous small nuclei lining Tissue the walls, while the interior of the tube (corresponding with the cell-vacuole) contains a fluid called latex, consisting of an emulsion of fine granules and drops of very various substances suspended in a watery medium in which various other substances (salts, sugars, rubber-producers, tannins, alkaloids and various enzymes) are dissolved.
The cell sap contains various substances in solution such as sugars, inulin, alkaloids, glucosides, organic acids and various inorganic salts.
The chief constituents of colchicum are two alkaloids, colchicine and veratrine.