THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



Vol. X, No. 8.] January, 1917. [ Jol'xi'^rs. 



Histology of Astragalus mollissimus. 



BY NEVA RITTER. 



"T OCO" in Spanish may be translated "crazy." The stock 



J— i on the range in the western part of America were, there- 

 fore, said to be "locoed" when they exhibited symptoms of a dis- 

 ease involving loss of muscular control. 



The first published account of the loco-weed disease was in the 

 Report of the Commissioner of Agriculture for October, 1873, by 

 Doctor Vasey. He attributed it to Astragali in California. 



From then on every year appeared some new article, more of 

 which were descriptions of the loco weeds and their effects on the 

 stock than reports of discoveries of the true cause of the disease. 



Professor Sayre ('86), of the University of Kansas, published 

 articles in the Transactions of the Kansas Academy of Science 

 and in the Report of the State Board of Agriculture describing 

 the loco weeds in Kansas and telling of their effects on stock. He 

 reported two loco weeds here, Astragalus and Oxytropis (Aragallus) . 

 He suggested the theory that the hairs on the leaves may by irri- 

 tation cause the disease. In 1888 he reported having used the 

 extract on himself and getting no resulting loco symptoms. In 

 1890 he separated some crystals which he said were inorganic and 

 were not the poisonous principle. In 1892 he reported traces of 

 alkaloid and said that loco weeds are not the cause of the disease 

 of the stock. In 1898 he thought a poison develops in the animal 

 which does not exist as such in the plant. In 1904 he put forth 

 three possibilities of the cause of the disease: 



(1) Irritation by hairs. 



(2) Disturbance to digestion by eating much loco weed in the early 



spring. 



(3) A poison develops during digestion. 



Kennedy ('88) found no alkaloid nor poisonous principle when 

 he used infusions in boiling water, dried powder, and an organic 



(197) 



