Jan. 1917 Poisonous Properties of Milk Vetch. 61 



All parts of the plant contain poison apparently quite 

 evenly distributed throughout. 



Data gathered from stockmen would indicate that this spe- 

 cies of vetch is poisonous to cattle and sheep. Nothing is 

 known in regard to its effect on horses. The laboratory has 

 obtained no direct evidence that sheep have been killed by eat- 

 ing it, although a number of suspicious cases are on record. 



During July, 1916, E.*B. Foster of Casper reported a loss 

 of nine calves and ten cows out of a herd of forty-one head. 

 He states, "No two acted in the same way. However, all evi r 

 denced signs of craziness. On some the effect would hardly 

 be noticed until one went near them, and then they would sud- 

 denly act frightened and in attempting to get away would 

 stumble and fall or have a fit." All animals which showed 

 signs of milk-vetch poisoning died. 



EXPERIMENTAL. 



The plant material submitted for investigation was secured 

 from Mr. Foster of Casper, Wyo. Green plants could have 

 been obtained in the vicinity of Laramie, but it seemed advisable 

 to deal with those authentically known to have given trouble. 



After drying, the seeds, pods, leaves, and stems, respect- 

 ively, were coarsely ground and placed in air-tight containers. 



Test for Hydrocyanic Acid. 



Five hundred grams of air-dried material were placed in a 

 flask and saturated with water. Steam was then passed into 

 the flask for a period of three hours. The distillate gave neg- 

 ative results for hydrocyanic acid. Tests were made upon 

 each part of the plant. The residue remaining in each case was 

 acidified with strong sulphuric acid and again treated as above. 

 Negative results were obtained for combined hydrocyanic acid. 



The distillates had an odor particularly disagreeable. The 

 distillate from the seeds yielded a small amount of volatile oil 

 which proved to be non-toxic in character. 



