It crystallizes in prisms, containing one molecule of water of crystallization, the anhydrous form melting at 234-235° C. Nitrous acid converts it into malic acid, [[Hooc Choh Ch 2 Cooh]].
(All except d represent vertical sections of sporangiophore or sorus.) canal the spermatozoid, which in the Ferns has been shown to be attracted by reason of its positive irritability to malic acid, passes and fuses with the ovum.
The character of the acidity, however, changes, the free tartaric acid gradually disappearing, forming bitartrate of potash and being otherwise broken up. On the other hand, the free malic acid increases and the tannin decreases.
It may be prepared by the oxidation of fats and of fatty acids by nitric acid, and is also a product of the fermentation of malic and tartaric acids.
Synthetically it may ba obtained by reducing malic or tartaric acids with hydriodic acid (R.