Barium, A Cause of the Loco-Weed Disease Part 11

=EFFECT OF THE AQUEOUS EXTRACT OF ASHED LOCO PLANTS.=

The filtrate from the ash from 200 grams of dried _Astragalus mollissimus_, from Imperial, Nebr., after similar treatment with acetic acid water and freed from free acid, killed a rabbit in several hours.

Hydrochloric acid also rendered the toxic agent of the ash soluble in water, but proved unsuitable for our work, as it was found impossible to obtain neutral residues by mere evaporation on the bath. At first one of the heavy metals or members of the H_{2}S group[161] was suspected, but on pa.s.sing H_{2}S into the slightly acid extract of the ash no active precipitate resulted, but the filtrate remained active.[162] A special Marsh test was, however, made for a.r.s.enic and antimony with negative results. A test for tungsten with zinc and hydrochloric acid proved negative.

Members of the ammonium sulphid group were then suspected, but while ammonium hydrate alone gave a heavy white precipitate, this precipitate, as also the black one with ammonium sulphid, proved inactive save when not thoroughly freed from acid (used for solution). The action of this ammonium sulphid precipitate on rabbits was watched for sixteen days, but without result. Nevertheless, the writer still suspected some of the rare earths.[163]

Sestini[164] had found that if certain plants were nourished with a solution of a beryllium salt, in the ash of these plants could be shown the presence of beryllium.

Two grams of beryllium chlorid were fed in aqueous solution to a rabbit weighing 1,800.2 grams. In four days this animal lost 241 grams and died. The stomach showed the same general pallor seen in chronic locoed rabbits, but no ulcers. The tests for beryllium by Sestini's method, however, failed to show beryllium in the active loco plants examined.

Thorium chlorid, cerium chlorid, and lanthanum chlorid in 2-gram doses and zirconium chlorid in 3-gram doses produced no chronic symptoms in rabbits or, in fact, any disturbance. t.i.tanium chlorid, 2.5 grams, evaporated in the air and then fed in an emulsion to a rabbit, also proved inactive, but this inactivity may have been due to its insolubility.

Thallium nitrate c. p., in aqueous solution, in 2-gram doses, killed a rabbit weighing 2,154.6 grams in two hours and fifteen minutes. The stomach in this case, while pink, was not hemorrhagic.

Zirconium chlorid has an astringent taste, and if fed repeatedly will cause the metallic astringent action. On boiling an acetic acid solution of the ash with sodium acetate a precipitate formed.[165]

The presence of zirconium was thus suspected and Dr. E. C. Sullivan, of the United States Geological Survey, estimated it to be present in the ash of a sample of _Aragallus lamberti_ in about 0.01 per cent zirconium oxid, with also 0.1 per cent t.i.tanium dioxid.[166]

Zirconium chlorid, 3 grams, was fed in aqueous solution to a rabbit weighing 850.5 grams. This rabbit lost 96 grams in seven days, and was then fed 3 grams more of the same solution and the following day 2 grams more. It died eight days later, weighing 656 grams. The stomach and intestines were contracted, but showed no ulcers. However, 4 grams killed a rabbit in two hours and thirty-two minutes.

The filtrate, after treating an active solution of the ash with hydrogen peroxid, proved active, thus showing that zirconium was not entirely responsible for the poisonous action.

Yttrium, while not found in the plant, was administered as yttrium chlorid to a rabbit weighing 1,530 grams in 2-gram doses in solution.

This animal gained 113.4 grams in five days.

Didymium chlorid c. p., in 3-gram doses, was fed to a rabbit weighing 1,020 grams. This rabbit lost 70 grams in four days.

The administration of manganese acetate[167] in 2-gram doses was followed by a gain in weight of a rabbit of 42.5 grams, while a dose of 3 grams killed a rabbit weighing 1,077 grams in two hours and thirty minutes. Wohlwill[168] has emphasized the fact that the members of the iron group owe their comparative harmlessness to not being absorbed by the gastro-intestinal tract.

No zinc was found in the plant.[169]

It is well recognized that pota.s.sium salts given hypodermically are decidedly toxic and that ammonium salts given per os will kill, so that the writer considered the possibility of other members of the group being responsible for the injurious action. The fact that the alkaline distillate of the plant proved inactive eliminated the ammonium salts.

Caesium chlorid c. p., 2 grams, was fed in aqueous solution to a rabbit weighing 1,077.2 grams. In six days this animal lost 255 grams in weight, when it died.[170]

A second rabbit, weighing 1,020.5 grams, was fed with 2 grams of the same solution and lost 368 grams in twenty-one days. The spectroscopic test, however, failed to show caesium in the ashed plant. Rubidium chlorid c. p., in 2-gram doses, proved inactive. The platinum chlorid precipitate from the extract of the plant proved inactive.

The fact that the filtrate after precipitation of the phosphates by tin and nitric acid and H_{2}S was active excluded the phosphoric acid radical, and the filtrate after treatment with BaCO_{3} and AgO being active excluded the H_{2}SO_{4} and HCl radicals as the toxic body.

Fluorine was proved to be absent.

A radio-active substance was suspected, but Dr. L. J. Briggs, Physicist of Bureau of Plant Industry, reported that the dried plant showed no special amount of radio-activity.[171]

Power and Cambier, Sayre, and Kennedy had previously called attention to the abundance of calcium in the plant, and the writer's investigations confirm this. Pharmacologists are averse to believing calcium given per os poisonous. The writer has, however, fed 5 grams of the acetate of calcium in solution to a rabbit weighing 652 grams. This animal died in two hours, with marked irritation of the stomach, the result being due to the so-called "salt action." Much larger amounts were fed in divided doses, but without injury. Calcium phosphate and calcium sulphate in 2-gram doses proved harmless to a rabbit weighing about 1,400 grams.

Three grams of magnesium acetate[172] were fed in solution for five successive days to a rabbit weighing 1,417 grams, but without apparent effect.

Strontium acetate c. p., in 2-gram doses, likewise caused no disturbance.[173] No strontium in any amount recognizable by chemical tests was proved in the plant. So that by a process of exclusion the writer was forced to think of barium as the main cause of the trouble.

The writer noted that if the ashed plant was extracted with H_{2}SO_{4} water and this extract freed from sulphuric acid with PbCO_{3} and H_{2}S the solution proved inactive to rabbits and also that after this extraction the acetic acid extract of the ash failed to kill. In other words, the sulphate of our body was insoluble in water. At times in pa.s.sing H_{2}S into active solutions of the ashed plant freed from the acetic acid by evaporation the filtrate and likewise the precipitate were inactive. Noyes and Bray[174] have noted that if H_{2}S is pa.s.sed into certain solutions in the presence of an oxydizing agent, such as ferric iron, H_{2}SO_{4} would be formed, which would throw any barium out of solution.

In one blood-pressure record made with a dog (vagi nerves cut), a rise in blood pressure (a characteristic physiological action of barium) was seen to follow the intravenous injection of the aqueous extract of the plant, in spite of its normal acid reaction.

Accidentally the writer found that Sprengel[175] had reported the presence of barium in _Astragalus exscapus_, a closely allied plant.

Barium has also been found in the vegetable world by Scheele in 1788, and later by Eckard,[176] who found it in beech, while Forchhammer[177]

proved it in birch, and Lutterkorth found it in the soil of the same area in which Eckard worked. Dworzak[178] noted the occurrence of traces of this element in wheat grown along the Nile, and Knop[179] found it in the soil. Doctor Balfour, of Khartum, Egypt, informed the writer that he knew of no cases in which this barium in wheat had produced poisoning.

Hornberger[180] found barium both in the red beech grown in Germany and in the soil on which these trees grew. It has also been claimed that various marine plants may take up barium from the sea.[181]

Hillebrand[182] has called attention to the fact that the igneous rocks of the Rocky Mountains showed a higher percentage of barium than rock from other portions of the United States, so that under these conditions one might expect the presence of barium in plants growing in this region. A sample of _Aragallus lamberti_ and one of _Astragalus mollissimus_ were sent to the Bureau of Chemistry for spectroscopic examination for various elements and they reported traces of barium in each.[183]

With these arguments the writer felt sure of the presence of barium, and the matter was discussed with Dr. E. C. Sullivan, of the United States Geological Survey, and he kindly corroborated the conclusions reached as to the presence of barium, controlling its presence by means of the spectroscope, and estimated it roughly as 0.1 per cent BaO in the ash of a sample of _Aragallus lamberti_ (6.3 milligrams BaSO_{4} in 4 grams ash). This determination was made by Hillebrand's method.

Kobert has antic.i.p.ated this result, saying that "all plants are in the position occasionally to take up barium combinations from the soil," and "the plants which thus contain barium may act injuriously to men and animals."[184]

FOOTNOTES:

[161] Swain, R. E., and Harkins, W. D. a.r.s.enic in Vegetation Exposed to Smelter Smoke. Journ. Amer. Chem. Soc., vol. 30, p. 915. 1908.--Harkins, W. D., and Swain, R. E. The Chronic a.r.s.enical Poisoning of Herbivorous Animals. Journ. Amer.

Chem. Soc., vol. 30, p. 928, 1908.

[162] A similar extract was sent to the Bureau of Chemistry, and that Bureau also reported an absence of the elements of the H_{2}S group.

[163] Bachem, C. Pharmakologisches uber einige Edelerden.

Arch. Internat. de Pharmacodyn., vol. 17, p. 363. 1907.

[164] Sestini, F. Esper. di Vegetaz. del Frumento con Sost.i.tuz. della Glucina alla Magnesia. Staz. Sper. Agrar.

Ital., vol. 20, p. 256. 1891.--Di alcuni Elementi Chimici Rari a Trovarsi nei Vegetabili. Staz. Sper. Agrar. Ital., vol. 15, p. 290. 1888.

NOTE.--The ammonium sulphid precipitate was very small if the phosphates were first removed with tin and nitric acid.

[165] Bohm, C. R. Darstellung d. seltenen Erden, vol. 1, p.

40. 1905.

[166] Wait, C. E. Occurrence of t.i.tanium. Journ. Amer. Chem.

Soc., vol. 18, p. 402. 1896.

NOTE.--There seem to be no records of any study of the pharmacological action of t.i.tanium.

[167] Compare Jaksch, R. v. Ueber Mangantoxikosen und Manganophobie. Munch. Med. Woch., p. 969. 1907.

[168] Wohlwill, F. Ueber d. Wirkung d. Metalle d.

Nickelgruppe. Arch. f. Exper. Path., vol. 56, p. 409. 1907.

[169] Laband, L. Zur Verbreitung des Zinkes im Pflanzenreiche. Zeits. f. Untersuch. d. Nahrungs u.

Genussmittel, vol. 4, p. 489. 1901.

[170] Caesium occurs in various plants and the possibility of poisoning by this element must be considered. It is hoped that the writer may be able to undertake a more thorough pharmacological study of this element.