Ink nuts are a particular species of galls formed by the larvae of a number of insects of the family of the nut-tree ( Cynipidae ) [1] on the young branches and leaves of some species of oak ( Quercus ). Porous formations are round or oblong in the form of growths with a diameter of 1.5-2 centimeters or more. Ink can cover the affected leaves in a bunch. Contain tannins (up to 70% of dry weight). The color may be greenish-yellowish, yellowish-white, yellowish, often with a red side. Because of their shape and color in English, they are called βoak applesβ ( English Oak apple ) [2] .
The structure of the gall is soft and loose, the internal contents are porous. In the very center of the gall there is a small chamber with a diameter of up to 5-7 mm, inside which the development of the larva occurs. With the help of an ovipositor, walnut-laying eggs lay eggs one by one in the flesh of the leaf. This causes increased growth of surrounding tissues, and as a result a gall is formed. A larva emerges from the egg, which eventually turns into an adult insect. The imago makes a move in the flesh of a gall and through it goes out. In Europe, the main primary sources of ink nuts are ordinary oak walnut ( Cynips quercusfolii ) and Biorhiza pallida , and in North America , the species Amphibolips confluenta and Atrusca bella [1] .
Ink nuts got their name because in the old days ink was made from them for writing [3] . Ink nuts contain many tannins [3] , which are natural polyphenols (substances that have several βOH groups connected to the benzene ring ). With tannins, iron salts form a complex colored in black - this was the basis for the production of ink [4] . According to the method of preparation, these inks were called glandular or iron-gall. Ink nuts have been known and used in ink production since at least the Roman Empire . For a long time, starting from the Middle Ages , these inks were standard for use in writing [5] ; they were most common from the 18th century until the mid- 20th century in connection with a gradual increase in literacy. For the manufacture of glandular ink, galls were infused in an acidic solution and iron filings were added. The process lasted up to a month. In order for the ink to "better fit" onto the paper, cherry gum was introduced into their composition. The ink obtained in this way was quite resistant - they faded little in the light and were waterproof. Despite the good resistance of ink to fading and washing, due to the presence of active substances in the composition, they cause the destruction of paper. In Russia, scribes of manuscripts also used βblacken with oak and ironβ - βironβ ink, which was prepared from iron sulfate by adding a decoction of ink nuts from oak leaves.
In addition, ink nuts were used to tan the skin and obtain astringent drugs [3] [6] .
In ancient Rome, unscrupulous sellers diluted copper sulfate with cheaper iron sulfate . In order to detect a fake, ink nuts were used: a black color betrayed the presence of iron in vitriol [4] .
Nowadays, galls are used to obtain tannin, used for medical purposes [4] .
Oak nuts on oak leaves
A bunch of ink nuts
Longitudinal section of an ink nut. The larva of the common oak- leaved oak tree ( Cynips quercusfolii ) is visible
Common Oak Walnut ( Cynips quercusfolii ) inside an ink nut
The imago of an ordinary oak- leaved oak-tree ( Cynips quercusfolii )
Notes
- β 1 2 Cranshaw, Whitney. Garden Insects of North America. - Princeton, New Jersey: Princeton University Press, 2004 .-- ISBN 0-691-09560-4 .
- β Around the World / Edited by N. N. Strakhov . - SPb. : Edition of the bookseller and typographer M.O. Wolf, 1866. - T. 6. - 388 p.
- β 1 2 3 Rimsky-Korsakov, Mikhail Nikolaevich . Ink Nuts // Brockhaus and Efron Encyclopedic Dictionary : in 86 volumes (82 volumes and 4 additional). - SPb. , 1903. - T. XXXVIIIa. - S. 604-606.
- β 1 2 3 Viter V.N. Oak Nuts (Ink Nuts) // Chemistry and Chemists. - 2013. - No. 4 .
- β Diringer, David. The Book Before Printing: Ancient, Medieval and Oriental. - Dover Publications, 1982. - P. 551-2.
- β Ink Nuts // Chagan - Aix-les-Bains. - M .: Soviet Encyclopedia, 1978. - (The Great Soviet Encyclopedia : [in 30 vol.] / Ch. Ed. A. M. Prokhorov ; 1969-1978, vol. 29).
Links
- Viter V.N. Oak Nuts (Ink Nuts) // Chemistry and Chemists. - 2013. - No. 4 .