U. S. DEPARTMENT OF AGRICULTURE.
BUREAU OF PLANT INDUSTRY—BULLETIN NO. 129.
B. T. GALLOWAY, Chief of Bureau.

BARIUM, A CAUSE OF THE
LOCO-WEED DISEASE.

BY

ALBERT C. CRAWFORD,

Pharmacologist, Poisonous-Plant Investigations.

Issued August 22, 1908.

WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1908.

BUREAU OF PLANT INDUSTRY.

• Physiologist and Pathologist, and Chief of Bureau, Beverly T. Galloway.
• Physiologist and Pathologist, and Assistant Chief of Bureau, Albert F. Woods.
• Laboratory of Plant Pathology, Erwin F. Smith, Pathologist in Charge.
• Investigations of Diseases of Fruits, Merton B. Waite, Pathologist in Charge.
• Laboratory of Forest Pathology, Haven Metcalf, Pathologist in Charge.
• Cotton and Truck Diseases and Plant Disease Survey, William A. Orton, Pathologist in Charge.
• Plant Life History Investigations, Walter T. Swingle, Physiologist in Charge.
• Cotton Breeding Investigations, Archibald D. Shamel and Daniel N. Shoemaker, Physiologists in Charge.
• Tobacco Investigations, Archibald D. Shamel, Wightman W. Garner, and Ernest H. Mathewson, in Charge.
• Corn Investigations, Charles P. Hartley, Physiologist in Charge.
• Alkali and Drought Resistant Plant Breeding Investigations, Thomas H. Kearney, Physiologist in Charge.
• Soil Bacteriology and Water Purification Investigations, Karl F. Kellerman, Physiologist in Charge.
• Bionomic Investigations of Tropical and Subtropical Plants, Orator F. Cook, Bionomist in Charge.
• Drug and Poisonous Plant Investigations and Tea Culture Investigations, Rodney H. True, Physiologist in Charge.
• Physical Laboratory, Lyman J. Briggs, Physicist in Charge.
• Crop Technology and Fiber Plant Investigations, Nathan A. Cobb, Crop Technologist in Charge.
• Taxonomic and Range Investigations, Frederick V. Coville, Botanist in Charge.
• Farm Management Investigations, William J. Spillman, Agriculturist in Charge.
• Grain Investigations, Mark Alfred Carleton, Cerealist in Charge.
• Arlington Experimental Farm, Lee C. Corbett, Horticulturist in Charge.
• Vegetable Testing Gardens, William W. Tracy, sr., Superintendent.
• Sugar-Beet Investigations, Charles O. Townsend, Pathologist in Charge.
• Western Agricultural Extension Investigations, Carl S. Scofield, Agriculturist in Charge.
• Dry-Land Agriculture Investigations, E. Channing Chilcott, Agriculturist in Charge.
• Pomological Collections, Gustavus B. Brackett, Pomologist in Charge.
• Field Investigations in Pomology, William A. Taylor and G. Harold Powell, Pomologists in Charge.
• Experimental Gardens and Grounds, Edward N. Byrnes, Superintendent.
• Foreign Seed and Plant Introduction, David Fairchild, Agricultural Explorer in Charge.
• Forage Crop Investigations, Charles V. Piper, Agrostologist in Charge.
• Seed Laboratory, Edgar Brown, Botanist in Charge.
• Grain Standardization, John D. Shanahan, Crop Technologist in Charge.
• Subtropical Laboratory and Garden, Miami, Fla., Ernst A. Bessey, Pathologist in Charge.
• Plant Introduction Garden, Chico, Cal., W. W. Tracy, jr., Assistant Botanist in Charge.
• South Texas Garden, Brownsville, Tex., Edward C. Green, Pomologist in Charge.
• Farmers’ Cooperative Demonstration Work, Seaman A. Knapp, Special Agent in Charge.
• Seed Distribution (Directed by Chief of Bureau), Lisle Morrison, Assistant in General Charge.

Editor, J. E. Rockwell.
Chief Clerk, James E. Jones.

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, Assistant 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 manuscript of a technical bulletin entitled “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 entity was freely doubted. Not only did this confusion characterize the field aspect of the matter, but the situation viewed from the