The Poisonous Properties of the 

 Two-Grooved Milk Vetch 



(Astragalus bisulcatus) 

 PART I. CHEMICAL. 



BY O. A. BEATH. 



INTRODUCTION. 



A brief account of the two-grooved milk vetch (Astra- 

 galus bisulcatus) is put in the form of a preliminary bulletin 

 at this time, largely to warn stockmen of its poisonous nature. 

 Authorities on poisonous plants make no mention of this par- 

 ticular vetch as being suspected of producing toxic effects. As 

 a consequence it is safe to conclude that certain conditions un- 

 doubtedly prevail which cause it to be extremely variable in its 

 toxicity. Moisture unquestionably influences the activity of 

 the toxic principle, inasmuch as it is readily soluble in water. 

 Certain stockmen have used this vetch for forage purposes 

 without any apparent ill effects, thereby illustrating the small 

 degree of danger when the plant is well dried. 



The attention of the research laboratory was called to the 

 plant's probable poisonous character rather late in the season 

 and as a result the data available at this time have to do only 

 with well matured material. Therefore, the seasonal factor is 

 yet to be determined. 



It is a matter of regret that direct feeding experiments 

 could not have been employed to verify the results obtained by 

 using water and alcoholic extracts. However, the project is to 

 be continued on a larger scale this coming summer. 



GENERAL CHARACTER OF THE PLANT. 

 Milk vetch is found growing on plains and in valleys 

 throughout the Rocky Mountain region. It appears during 

 the month of May and goes to seed the latter part of July. 

 The following description of the plant is given in Bulletin No. 

 76 of the Wyoming Experiment Station : 



