Nut-galls

C7H6O5. Colourless crystals with one molecule of water, m.p. 253" C, sparingly soluble in water and alcohol. It occurs free in woody tissue, in gall-nuts and in tea, and is a constituent of the tannins, from which it can be obtained by fermentation or by acid hydrolysis. It gives a blue-black colour with Fe and is used in the manufacture 6f inks. On heating it gives pyrogallol. 

Vegetable-tanning materials in commercial quantities come from many different countries. Quebracho is a principal tanning material from South America. Wattie or Mimosa is suppHed from several African sources. India and other Asian countries supply a variety of materials including Myrabolans, Gall Nuts, and Tara Pods (3). 

Eich amt, n gaging office, office of weights and measures. apfel, m. oak gall, gall nut. baum, m. oak tree. 

Many dyes that have no chemical affinity to fibrous substrates can be attached to such substrates by intermediary (go-between) substances known as mordants. These are either inorganic or organic substances that react chemically with the fibers as well as with the dyes and thus link the dyes to the fibers. Mordants are traditionally classified into two main classes, acid and metallic mordants. The acid mordants are organic substances that contain tannins (see Textbox 64) as for example, gall nuts and sumac. The metallic mordants are inorganic substances, mostly mineral oxides and salts that include metal atoms in their composition. Table 94 lists mordants of both these types, which have been used since antiquity. 

William Powder. Expl formulation contg K chlorate 57.15, KCN 19.05, starch 7.14, erode mineral oil 5.95, gall nuts 5.95, K dichromate 2.38 and charcoal 2.38%... 

One of the earliest references to a reaction in solution, which, as we now realize, depends upon the formation of a coordination compound, was recorded by Pliny who stated that the adulteration of copper sulfate by iron sulfate could be detected by testing with a strip of papyrus soaked in gall-nuts, when a black colour developed if iron were present. A. Libavius (1540-1616) noted how ammmonia present in water could be detected by the blue colour formed with a copper salt and A. Jacquelain (1846) actually determined copper salts in terms of the blue colour formed on adding ammonia. Later developments used coordination compounds formed from ethylenediamine and other polyamines.3 T. J. Herapath determined iron(III) as its red isothiocyanate complex in 1852 and the basic procedure is used today.3... 

As soon as chemical substances of plant or mineral origin became the objects of commerce, the need for what we nowadays think of as quality control became evident, for the realities of human nature soon ensured that problems of adulteration, false weights, and even plain deception had to be taken into account. Thus, Phny (23 79 ad) recorded that the adulteration of copper sulfate by iron sulfate could be detected by testing a solution with a strip of papyrus soaked in gall-nuts, which blackened if iron was present. 

In cases of poisoning by opium, the stomach pump should first be used, or an emetic of sulphate of zinc given the patient must be kept awake by continual walking between attendants after the vomiting, cold water may be poured on the face and chest, and an infusion of gall-nuts given, followed by brandy and coffee. Artificial respiration may succeed when all other means have failed. 

Gallo-tannic Acid.—One of these is gallo-tannic acid, also known as simply tannic acid, or tannin, also as di-gallic acid. It is found in gall-nuts and in tea and yields gallic acid on hydrolysis. 

Pyrogallic acid tannins which yield tannic acids convertible into gallic and pyrogallic acids. These tannins give a blue-black color with ferric chloride and give no precipitate with bromine water. They also form a bloom on the leather from hides which have been treated with them. These include tannins of gall-nuts, sumach, oak and chestnut wood. 

Tannic acid in tea (SECTION 616).—Pour about 50 cc. of boiling water onto about 1 gram of tea. After 2 minutes decant off the clear solution to 5 cc. of it add 2 drops of ferric chloride solution. If the shade of the color produced can not be clearly seen, dilute with water. Compare the color with that produced by the gall-nut tannic acid in experiment (a) above. Add 5 cc. of the solution to a dilute solution of gelatin. Compare the behavior of the tannic acid from tea with that from gall-nuts. 

Thus, if diluted alcohol ue poured over powder of mynh, in tho cylinder of the percolator, the fluid which first drops into tho receiver is a solution of an oily consistence chiefly composed of resin and volatile oil dissolved in alcohol. In like manner when the powder of gall-nuts is treated in the some way by hydrated sulphuric other, two layeVe of fluid aro obtained, one of which is a highly concentrated solution of tannin in the water of tho ether, and the other a weak solution of the same principlo in pure ether. In all cases, therefore, in which it is not otherwise directed, it is absolutely necessary to agitate the several portions of the liquid obtain by... 

Compoxxnd Gall Ointment. Rub together (5 drachms very finely powdered gall-nuts, 14 drachms powdered" opium, and 6 ounces lard. 

Gallic acid—Acidum gallioum U. 8.)—C Ha(OH)sCOOH—170— exists in nature in certain leaves, seeds, and fruits. It is best obtained from gall-nuts, which contain its glucosid, gallotannie acid (q.v.). It can be obtained from salicylic acid. 

Tannic Acids.—The name tannic acid or tannin is applied to a number of vegetable acids which are widely distributed in nature. Tannins occur in the bark of trees and in the leaves and roots of plants. The chief commercial sources of tannin are gall-nuts, sumach, oak and hemlock bark, and a number of plants and trees which grow in India and South America. 

Gallotannic acid separated from gall-nuts by extraction with alcohol, ether, and water, is obtained as a colorless amorphous mass or light yellow scales. It is soluble in six parts of cold water, and is precipitated by dilute hydrochloric acid or sodium... 

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