200 THE UNIVERSITY SCIENCE BULLETIN. 



noticing the cuts at all. They finally forget to drink even, and 

 slowly starve to death, hunting loco weeds all the time, and eating 

 nothing else. 



If taken from the loco weeds at first they may be cured by shut- 

 ting them up and feeding, but after the habit has become firmly 

 fixed they are incurable. Prophylaxis is to rid the pasture of 

 loco weeds, but this is practical only in small fenced lots. If fed 

 plenty, so they need no more, in the winter, the habit is not nearly 

 so readily acquired. Loco weeds are usually first eaten in late 

 winter or early spring when the grass is dried up and these plants 

 are still green. 



One suggested possibility is that an alkaloid is the cause of the 

 toxicity. Some analyses have shown it, others not. Dean Sayre 

 has found a trace of alkaloid, but as much or more in alfalfa. 

 Miss Watson ( 78) found an alkaloidal reaction in the root, also a 

 resinous body. Power and Cambier ('91) found toxic alkaloids, 

 together with volatile oil, acetic acid, resin, albuminoid, and 

 globulin. 



Crawford ('08), while working to find the cause of loco poison- 

 ing, discovered a trace of barium, which was verified by spectro- 

 scopic examination. He. measured .01 per cent barium oxide in 

 the ash, which indicated 1.56 milligrams of barium sulphate in 

 1 gram of ash. In some of the soils in that vicinity he found, by 

 similar examination, no trace of barium, nor in the well water. 

 His experimental results show that barium in the proper amounts, 

 as well as loco weeds, will kill animals; so his conclusion is that 

 barium in loco weeds causes their toxicity. He removed barium 

 with sulphuric acid and found the solution harmless. His. extract 

 of the dried material was not always active, which fact he thinks 

 means that there is something in the fresh plant which aids the 

 solution of the barium. His theoretical antidote is sulphuric acid. 



Working on this basis. Marsh ('12) experimented with three 

 lots of cattle. One lot were under normal pasture conditions; 

 one was given drinking water containing the amount of sulphuric 

 acid calculated to neutralize the amount of barium eaten in loco 

 weed; the other lot was given drinking water containing a like 

 amount of magnesium sulphate. The same proportion of each lot 

 became locoed, thus showing that neither sulphuric acid nor mag- 

 nesium sulphate are antidotes, as they should be if barium is the 

 cause of the toxicity, so he makes the statement that barium is 

 not the poison. 



