Barium, A Cause of the Loco-Weed Disease.

by Albert Cornelius Crawford.

POISONOUS-PLANT INVESTIGATIONS.

SCIENTIFIC STAFF.

Rodney H. True, _Physiologist in Charge_.

C. Dwight Marsh, _Expert in Charge of Field Investigations_.

Albert C. Crawford, _Pharmacologist_.

Arthur B. Clawson, _Expert in Field Investigations_.

Ivar Tidestrom, _a.s.sistant Botanist, in Cooperation with Forest Service_.

LETTER OF TRANSMITTAL.

U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF PLANT INDUSTRY, OFFICE OF THE CHIEF, _Washington, D. C., April 10, 1908_.

SIR: I have the honor to transmit herewith the ma.n.u.script of a technical bulletin ent.i.tled "Barium, a Cause of the Loco-Weed Disease," prepared by Dr. A. C. Crawford, Pharmacologist, under the direction of Dr. Rodney H. True, Physiologist in Charge of Poisonous-Plant Investigations, and to recommend that it be published as Bulletin No. 129 of the series of this Bureau.

For many years the stockmen in many parts of the West have reported disastrous consequences following the eating of so-called loco weeds characteristic of the regions involved. While many have doubted any causal relation between the plants in question and the stock losses, the reality of the damage has remained and has seemed to require a thoroughgoing sifting of the evidence concerning the part played by the plants. Accordingly, in the spring of 1905 a station for the experimental study of the problem was established at Hugo, Colo., in charge of Dr. C. Dwight Marsh, Expert, in cooperation with the Colorado Agricultural Experiment Station. Later a further feeding experiment was undertaken at Imperial, Nebr., in cooperation with the Nebraska Agricultural Experiment Station. Parallel with the feeding work in the field, laboratory work, designed to test under laboratory conditions the poisonous action of the plants from given areas, was undertaken at Washington by Dr. A. C. Crawford, Pharmacologist. A further phase of his part of the work was an attempt to ascertain the nature of such poisonous substance or substances as might occur in the loco plants.

In both of these lines of work Doctor Crawford has been successful, and the technical results of his work are here collected.

Respectfully,

B. T. GALLOWAY, _Chief of Bureau_.

Hon. JAMES WILSON, _Secretary of Agriculture_.

INTRODUCTORY STATEMENT.

A scientific understanding of the so-called loco-weed disease has been demanded and sought after for several decades for most practical purposes, but, in spite of the great amount of attention which this problem has received, no general agreement has been found among the results obtained. The field investigations have given such contradictory evidence that until the Bureau of Plant Industry of the Department of Agriculture turned its attention to the matter the whole subject of the loco disease was regarded by many as a kind of delusion and the existence of a distinct ent.i.ty was freely doubted. Not only did this confusion characterize the field aspect of the matter, but the situation viewed from the standpoint of laboratory study was also much obscured.

Some investigators claimed to have separated poisonous substances of various sorts from the loco weeds, while others of equal scientific standing denied the presence of any poisonous substance in the plants under general suspicion--the so-called loco weeds.

In view of the great seriousness of the loco situation from the standpoint of the stock interests, an active campaign both in the line of feeding experiments in the field and laboratory study at Washington was undertaken by the Office of Poisonous-Plant Investigations of the Bureau of Plant Industry.

The feeding experiments carried out at Hugo, Colo., in cooperation with the Colorado Agricultural Experiment Station, before the close of the first season developed evidence that there was in reality such a thing as a loco disease. The investigator in charge was enabled to describe the disease in its most important manifestations and made it possible to sift the facts from the large number of contradictory statements in the literature.

The laboratory work, undertaken and carried on simultaneously, consisted of a pharmacological study, under laboratory conditions and with the usual laboratory subjects, of the action of plant material sent in from the field. The acute phase of loco-weed poisoning, as well as a more prolonged type of the disease, was studied. In plants found in this preliminary feeding to be harmful, the poisonous principle was sought, with the very striking results fully described in this paper. The demonstration of the presence of barium in the plants was followed by barium feeding, with the production of symptoms which agreed with those produced in the laboratory with loco extracts and in the field experiments with the loco plants as seen growing on the range. By comparing these laboratory results with those produced in connection with the field work, it became possible to sift the wheat from the chaff in the ma.s.s of contradictory evidence detailed in the literature of this subject.

The practical importance of the discovery of the true nature of the active poisonous principle of the loco weeds is very great. It not only sheds light on the loco situation and enables one to explain many hitherto inexplicable things, but it also adds much to our knowledge of barium in its medical bearings. It opens up most important problems concerning the soils and the relation of the flora to them. It should be borne in mind that although barium is shown to be chiefly responsible for the poisonous properties of loco weeds in eastern Colorado, it is entirely possible that in other regions other substances may be equally or even more significant. This discovery also seems likely to provide a basis for a rational treatment of locoed stock. Unfortunately, the discovery of the fact that barium is the poisonous const.i.tuent of loco weeds came too late to aid in the search for remedial measures on the range during the period covered by this report, but those empirically arrived at have received additional support from these laboratory results.

Thus the work in field and laboratory, undertaken after repeated attempts and discouraging failures by others, has yielded results to persistent scientific research and promises practical aid to the now suffering live-stock interests. The results of the laboratory work are presented in this bulletin.

RODNEY H. TRUE, _Physiologist in Charge_.

BARIUM, A CAUSE OF THE LOCO-WEED DISEASE.

=GEOGRAPHICAL DISTRIBUTION OF THE LOCO-WEED DISEASE AND ALLIED CONDITIONS.=

In our Western States there is a marked annual loss of stock due to various causes. Some of these animals die in a condition known as "locoed," a term derived from the Spanish word "loco," meaning foolish or crazy.

This disorder extends from Montana to Texas and Mexico, and from Kansas and Nebraska to California.[1]

In 1898 the United States Department of Agriculture sent out, under the immediate direction of Mr. V. K. Chesnut, a request for information concerning the ravages of the loco disease. It was found that in the ten States of California, Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, Texas, and Wyoming the loss in 1898 was $144,850. Of this amount, $117,300 was attributed to Colorado alone; in fact, the disorder spread so that this State expended more than $200,000 in two years and over $425,000 in a period of nine years in attempts to eradicate the loco plants, the supposed cause of the trouble.[2]

The loss in one area of 35 by 120 miles in southwestern Kansas amounted to 25,000 cattle in 1883.[3] This loss in stock has been so great that the raising of horses has of necessity been abandoned in certain areas on account of the prevalence of these loco weeds.

It is difficult to obtain accurate data, as the ranchmen believe that any information as to the prevalence of the disorder would interfere with the value of their stock.[4]

Dr. James Fletcher, of the Central Experimental Farm, Ottawa, Canada, testified before the Select Standing Committee on Agriculture and Colonization that he had never seen a case in the North-west of a Canadian bred animal being locoed, although the loco plants were prevalent. He explained this absence of loco disease by the abundance of gra.s.s on the range, because of which the animals do not acquire the habit of eating loco plants.[5] Cases have been reported, however, in Manitoba.[6]

FOOTNOTES:

[1] Stalker, M. The "Loco" Plant and Its Effect on Animals.

Bur. Animal Industry, 3d Ann. Rept. (1886), p. 271. 1887.

[2] Bur. Animal Industry, 6th and 7th Ann. Repts. (1889 and 1890), p. 272. 1891.

[3] Day, M. G. Loco-Weed. In F. P. Foster's Reference-Book of Practical Therapeutics, vol. 1, p. 587. 1896.

[4] O'Brine, D. Progress Bulletin on the Loco and Larkspur.

Colo. State Agric. Coll. Bul. 25, p. 18. 1893.

[5] Fletcher, J. Evidence Before the Select Standing Comminttee on Agriculture and Colonization. Ottawas, 1905, p.