374 UNIVERSITY OF VIRGINIA PUBLICATIONS 



known distribution of the parasitic diseases of sheep, but complete sys- 

 tematic studies of the prevaihng parasitic diseases of Western live stock 

 have not been made and knowledge upon this subject is incomplete. With 

 regard to poisonous plants it has been shown in a number of publications 

 from the Bureau of Plant Industry such as those by V. K. Chesnut and 

 by Chesnut and Wilcox that there are several widespread and highly 

 poisonous plants on the Western plains which occasionally cause great 

 losses among stock. 



The ranchmen themselves attribute great losses to the poisonous ac- 

 tion of the locoweed, and this matter has given rise to much writing. The 

 botanical characteristics and distribution of the various locoweeds were 

 studied by Chesnut and others. After Chesnut's report appeared — in 

 which he also described the general sjinptoms of the locoed animals — I 

 was engaged by the Bureau of Plant Industry to study locoed animals in 

 Montana for the purpose first, of giving a clear description of the sjinptoms 

 characteristic of locoweed poisoning, and second, of locating and describ- 

 ing the anatomical changes produced in animals from eating the weed. As 

 the result of my findings it proved necessary to conduct a feeding experi- 

 ment in order to settle the vexed question as to whether it is possible to 

 obtain uncomplicated cases of genuine locoweed poisoning. Inasmuch as 

 other publications have appeared upon the subject of locoweed poisoning 

 since 1903 and 1904, when my studies were made, I conclude this report with 

 a review of the recent literature and with a discussion of the loco problem, 

 as it confronts us todaj'. 



The report falls into several divisions: 



A. Information obtained from the ranchmen and from literature. 



B. The results of examinations of typical "locoed" sheep as thej^ 

 were met with on the ranches. 



C. The description of feeding experiments and the results obtained 

 from them. 



D. Discussion of the parasitic diseases encountered. 



E. A review of recent publications dealing with loco disease. 



F. The present status of the "Loco problem. " 



i 



